Descargar archivo usando Javascript / jQuery

Tengo un requisito muy similar especificado aquí .

Necesito que el navegador del usuario inicie una descarga manualmente cuando $('a#someID').click();

Pero no puedo usar el window.hrefmétodo, ya que reemplaza el contenido actual de la página con el archivo que está intentando descargar.

En cambio, quiero abrir la descarga en una nueva ventana / pestaña. ¿Cómo es esto posible?

Usa un invisible <iframe>:

<iframe id="my_iframe" style="display:none;"></iframe>
<script>
function Download(url) {
    document.getElementById('my_iframe').src = url;
};
</script>

Para forzar al navegador a descargar un archivo que de otro modo sería capaz de procesar (como archivos HTML o de texto), necesita que el servidor configure el Tipo MIME del archivo en un valor sin sentido, como application/x-please-download-meo alternativamente application/octet-stream, que se utiliza para binarios arbitrarios datos.

Si solo desea abrirlo en una nueva pestaña, la única forma de hacerlo es que el usuario haga clic en un enlace con su targetatributo establecido en _blank.

En jQuery:

$('a#someID').attr({target: '_blank', 
                    href  : 'http://localhost/directory/file.pdf'});

Cada vez que se hace clic en ese enlace, descargará el archivo en una nueva pestaña / ventana.

Actualización de navegadores modernos 2019

Este es el enfoque que ahora recomendaría con algunas advertencias:

• Se requiere un navegador relativamente moderno
• Si se espera que el archivo sea muy grande , probablemente debería hacer algo similar al enfoque original (iframe y cookie) porque algunas de las operaciones a continuación podrían consumir memoria del sistema al menos tan grande como el archivo que se descarga y / u otra CPU interesante efectos secundarios.

fetch('https://jsonplaceholder.typicode.com/todos/1')
  .then(resp => resp.blob())
  .then(blob => {
    const url = window.URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.style.display = 'none';
    a.href = url;
    // the filename you want
    a.download = 'todo-1.json';
    document.body.appendChild(a);
    a.click();
    window.URL.revokeObjectURL(url);
    alert('your file has downloaded!'); // or you know, something with better UX...
  })
  .catch(() => alert('oh no!'));

Enfoque basado en jQuery / iframe / cookie original de 2012

He creado el complemento de descarga de archivos jQuery ( Demo ) ( GitHub ) que también podría ayudar con su situación. Funciona de manera bastante similar con un iframe, pero tiene algunas características interesantes que he encontrado bastante útiles:

• Muy fácil de configurar con imágenes agradables (jQuery UI Dialog, pero no es obligatorio), todo se prueba también

• El usuario nunca abandona la misma página desde la que inició la descarga de un archivo. Esta característica se está volviendo crucial para las aplicaciones web modernas

• Las funciones successCallback y failCallback le permiten ser explícito sobre lo que el usuario ve en cualquier situación

• En conjunción con jQuery UI, un desarrollador puede mostrar fácilmente un modal diciéndole al usuario que se está produciendo una descarga de archivos, disolver el modal después de que comience la descarga o incluso informar al usuario de manera amigable de que se ha producido un error. Vea la demostración para ver un ejemplo de esto. ¡Espero que esto ayude a alguien!

Aquí hay una demostración de caso de uso simple usando la fuente del complemento con promesas. La página de demostración también incluye muchos otros ejemplos de 'mejor UX'.

$.fileDownload('some/file.pdf')
    .done(function () { alert('File download a success!'); })
    .fail(function () { alert('File download failed!'); });

function downloadURI(uri, name) 
{
    var link = document.createElement("a");
    // If you don't know the name or want to use
    // the webserver default set name = ''
    link.setAttribute('download', name);
    link.href = uri;
    document.body.appendChild(link);
    link.click();
    link.remove();
}

Compruebe si su (s) navegador (es) de destino ejecutarán el fragmento anterior sin problemas:
http://caniuse.com/#feat=download

Me sorprende que no mucha gente sepa sobre el atributo de descarga de un elemento. Por favor, ayuda a correr la voz al respecto! Puede tener un enlace html oculto y simular un clic en él. Si el enlace html tiene el atributo de descarga, descarga el archivo, no lo ve, pase lo que pase. Aquí está el código. Descargará una imagen de gato si puede encontrarla.

document.getElementById('download').click();

<a href="https://docs.google.com/uc?id=0B0jH18Lft7ypSmRjdWg1c082Y2M" download id="download" hidden></a>

Nota: Esto no es compatible con todos los navegadores: http://www.w3schools.com/tags/att_a_download.asp

Recomiendo usar el downloadatributo para descargar en lugar de jQuery:

<a href="your_link" download> file_name </a>

Esto descargará su archivo, sin abrirlo.

Si ya está usando jQuery, podría aprovecharlo para producir un fragmento más pequeño.
Una versión jQuery de la respuesta de Andrew:

var $idown;  // Keep it outside of the function, so it's initialized once.
downloadURL : function(url) {
  if ($idown) {
    $idown.attr('src',url);
  } else {
    $idown = $('<iframe>', { id:'idown', src:url }).hide().appendTo('body');
  }
},
//... How to use it:
downloadURL('http://whatever.com/file.pdf');

Funciona en Chrome, Firefox e IE8 y superior.

var link=document.createElement('a');
document.body.appendChild(link);
link.href=url ;
link.click();

Ejemplo simple usando un iframe

function downloadURL(url) {
    var hiddenIFrameID = 'hiddenDownloader',
        iframe = document.getElementById(hiddenIFrameID);
    if (iframe === null) {
        iframe = document.createElement('iframe');
        iframe.id = hiddenIFrameID;
        iframe.style.display = 'none';
        document.body.appendChild(iframe);
    }
    iframe.src = url;
};

Luego simplemente llame a la función donde quiera:

downloadURL('path/to/my/file');

Esto podría ser útil si no necesita navegar en otra página. Esta es la función base de JavaScript, por lo que se puede usar en cualquier plataforma donde el backend esté en Javascript

window.location.assign('any url or file path')

Solo siete años después, aquí viene una solución jQuery de una línea que usa un formulario en lugar de un iframe o enlace:

$('<form></form>')
     .attr('action', filePath)
     .appendTo('body').submit().remove();

He probado esto en

• Cromo 55
• Firefox 50
• Edge IE8-10
• iOS 10 (Safari / Chrome)
• Android Chrome

Si alguien conoce algún inconveniente con esta solución, me alegraría saber de ellos.

Demo completa:

<html>
<head><script src="https://code.jquery.com/jquery-1.11.3.js"></script></head>
<body>
<script>
    var filePath = window.prompt("Enter a file URL","http://jqueryui.com/resources/download/jquery-ui-1.12.1.zip");
    $('<form></form>').attr('action', filePath).appendTo('body').submit().remove();
</script>
</body>
</html>

No sé si la pregunta es demasiado antigua, pero establecer window.location en una URL de descarga funcionará, siempre que el tipo de mime de descarga sea correcto (por ejemplo, un archivo zip).

var download = function(downloadURL) {

   location = downloadURL;

});

download('http://example.com/archive.zip'); //correct usage
download('http://example.com/page.html'); //DON'T

Terminé usando el fragmento de abajo y funciona en la mayoría de los navegadores, aunque no probado en IE.

let data = JSON.stringify([{email: "test@domain.com", name: "test"}, {email: "anothertest@example.com", name: "anothertest"}]);

let type = "application/json", name = "testfile.json";
downloader(data, type, name)

function downloader(data, type, name) {
	let blob = new Blob([data], {type});
	let url = window.URL.createObjectURL(blob);
	downloadURI(url, name);
	window.URL.revokeObjectURL(url);
}

function downloadURI(uri, name) {
    let link = document.createElement("a");
    link.download = name;
    link.href = uri;
    link.click();
}

Actualizar

function downloadURI(uri, name) {
    let link = document.createElement("a");
    link.download = name;
    link.href = uri;
    link.click();
}

function downloader(data, type, name) {
    let blob = new Blob([data], {type});
    let url = window.URL.createObjectURL(blob);
    downloadURI(url, name);
    window.URL.revokeObjectURL(url);
}

Para mejorar la respuesta de Imagine Breaker, esto es compatible con FF e IE:

var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);

function downloadURI(uri, name) {
    var link = document.createElement("a");
    link.download = name;
    link.href = uri;
    link.dispatchEvent(evt);
}

En otras palabras, simplemente use una dispatchEventfunción en lugar de click();

Tal vez solo haga que su JavaScript abra una página que solo descarga un archivo, como cuando arrastra un enlace de descarga a una nueva pestaña:

Window.open("https://www.MyServer.
Org/downloads/ardiuno/WgiWho=?:8080")

Con la ventana abierta, abra una página de descarga que se cierra automáticamente.

A continuación se encuentra el código más completo y funcional (probado) para descargar datos para Firefox, Chrome e IE Code. Supongamos que los datos están en texarea campo, que tiene id = 'textarea_area' y el nombre de archivo es el nombre del archivo donde se pueden descargar los datos.

function download(filename) {
    if (typeof filename==='undefined') filename = ""; // default
    value = document.getElementById('textarea_area').value;

    filetype="text/*";
    extension=filename.substring(filename.lastIndexOf("."));
    for (var i = 0; i < extToMIME.length; i++) {
        if (extToMIME[i][0].localeCompare(extension)==0) {
            filetype=extToMIME[i][1];
            break;
        }
    }


    var pom = document.createElement('a');
    pom.setAttribute('href', 'data: '+filetype+';charset=utf-8,' + '\ufeff' + encodeURIComponent(value)); // Added BOM too
    pom.setAttribute('download', filename);


    if (document.createEvent) {
        if (navigator.userAgent.indexOf('MSIE') !== -1 || navigator.appVersion.indexOf('Trident/') > 0) { // IE
            blobObject = new Blob(['\ufeff'+value]);
            window.navigator.msSaveBlob(blobObject, filename);
        } else { // FF, Chrome
            var event = document.createEvent('MouseEvents');
            event.initEvent('click', true, true);
            pom.dispatchEvent(event);
        }
    } else if( document.createEventObject ) { // Have No Idea
        var evObj = document.createEventObject();
        pom.fireEvent( 'onclick' , evObj );
    } else { // For Any Case
        pom.click();
    }

}

y luego solo llama

<a href="javascript:download();">Download</a>

Para descargar Iniciando.

La matriz para configurar el tipo MIME correcto para el diálogo de descarga PUEDE SER siguiente:

// ----------------------- Extensions to MIME --------- //

        // List of mime types
        // combination of values from Windows 7 Registry and 
        // from C:\Windows\System32\inetsrv\config\applicationHost.config
        // some added, including .7z and .dat
    var extToMIME = [
        [".323", "text/h323"],
        [".3g2", "video/3gpp2"],
        [".3gp", "video/3gpp"],
        [".3gp2", "video/3gpp2"],
        [".3gpp", "video/3gpp"],
        [".7z", "application/x-7z-compressed"],
        [".aa", "audio/audible"],
        [".AAC", "audio/aac"],
        [".aaf", "application/octet-stream"],
        [".aax", "audio/vnd.audible.aax"],
        [".ac3", "audio/ac3"],
        [".aca", "application/octet-stream"],
        [".accda", "application/msaccess.addin"],
        [".accdb", "application/msaccess"],
        [".accdc", "application/msaccess.cab"],
        [".accde", "application/msaccess"],
        [".accdr", "application/msaccess.runtime"],
        [".accdt", "application/msaccess"],
        [".accdw", "application/msaccess.webapplication"],
        [".accft", "application/msaccess.ftemplate"],
        [".acx", "application/internet-property-stream"],
        [".AddIn", "text/xml"],
        [".ade", "application/msaccess"],
        [".adobebridge", "application/x-bridge-url"],
        [".adp", "application/msaccess"],
        [".ADT", "audio/vnd.dlna.adts"],
        [".ADTS", "audio/aac"],
        [".afm", "application/octet-stream"],
        [".ai", "application/postscript"],
        [".aif", "audio/x-aiff"],
        [".aifc", "audio/aiff"],
        [".aiff", "audio/aiff"],
        [".air", "application/vnd.adobe.air-application-installer-package+zip"],
        [".amc", "application/x-mpeg"],
        [".application", "application/x-ms-application"],
        [".art", "image/x-jg"],
        [".asa", "application/xml"],
        [".asax", "application/xml"],
        [".ascx", "application/xml"],
        [".asd", "application/octet-stream"],
        [".asf", "video/x-ms-asf"],
        [".ashx", "application/xml"],
        [".asi", "application/octet-stream"],
        [".asm", "text/plain"],
        [".asmx", "application/xml"],
        [".aspx", "application/xml"],
        [".asr", "video/x-ms-asf"],
        [".asx", "video/x-ms-asf"],
        [".atom", "application/atom+xml"],
        [".au", "audio/basic"],
        [".avi", "video/x-msvideo"],
        [".axs", "application/olescript"],
        [".bas", "text/plain"],
        [".bcpio", "application/x-bcpio"],
        [".bin", "application/octet-stream"],
        [".bmp", "image/bmp"],
        [".c", "text/plain"],
        [".cab", "application/octet-stream"],
        [".caf", "audio/x-caf"],
        [".calx", "application/vnd.ms-office.calx"],
        [".cat", "application/vnd.ms-pki.seccat"],
        [".cc", "text/plain"],
        [".cd", "text/plain"],
        [".cdda", "audio/aiff"],
        [".cdf", "application/x-cdf"],
        [".cer", "application/x-x509-ca-cert"],
        [".chm", "application/octet-stream"],
        [".class", "application/x-java-applet"],
        [".clp", "application/x-msclip"],
        [".cmx", "image/x-cmx"],
        [".cnf", "text/plain"],
        [".cod", "image/cis-cod"],
        [".config", "application/xml"],
        [".contact", "text/x-ms-contact"],
        [".coverage", "application/xml"],
        [".cpio", "application/x-cpio"],
        [".cpp", "text/plain"],
        [".crd", "application/x-mscardfile"],
        [".crl", "application/pkix-crl"],
        [".crt", "application/x-x509-ca-cert"],
        [".cs", "text/plain"],
        [".csdproj", "text/plain"],
        [".csh", "application/x-csh"],
        [".csproj", "text/plain"],
        [".css", "text/css"],
        [".csv", "text/csv"],
        [".cur", "application/octet-stream"],
        [".cxx", "text/plain"],
        [".dat", "application/octet-stream"],
        [".datasource", "application/xml"],
        [".dbproj", "text/plain"],
        [".dcr", "application/x-director"],
        [".def", "text/plain"],
        [".deploy", "application/octet-stream"],
        [".der", "application/x-x509-ca-cert"],
        [".dgml", "application/xml"],
        [".dib", "image/bmp"],
        [".dif", "video/x-dv"],
        [".dir", "application/x-director"],
        [".disco", "text/xml"],
        [".dll", "application/x-msdownload"],
        [".dll.config", "text/xml"],
        [".dlm", "text/dlm"],
        [".doc", "application/msword"],
        [".docm", "application/vnd.ms-word.document.macroEnabled.12"],
        [".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"],
        [".dot", "application/msword"],
        [".dotm", "application/vnd.ms-word.template.macroEnabled.12"],
        [".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"],
        [".dsp", "application/octet-stream"],
        [".dsw", "text/plain"],
        [".dtd", "text/xml"],
        [".dtsConfig", "text/xml"],
        [".dv", "video/x-dv"],
        [".dvi", "application/x-dvi"],
        [".dwf", "drawing/x-dwf"],
        [".dwp", "application/octet-stream"],
        [".dxr", "application/x-director"],
        [".eml", "message/rfc822"],
        [".emz", "application/octet-stream"],
        [".eot", "application/octet-stream"],
        [".eps", "application/postscript"],
        [".etl", "application/etl"],
        [".etx", "text/x-setext"],
        [".evy", "application/envoy"],
        [".exe", "application/octet-stream"],
        [".exe.config", "text/xml"],
        [".fdf", "application/vnd.fdf"],
        [".fif", "application/fractals"],
        [".filters", "Application/xml"],
        [".fla", "application/octet-stream"],
        [".flr", "x-world/x-vrml"],
        [".flv", "video/x-flv"],
        [".fsscript", "application/fsharp-script"],
        [".fsx", "application/fsharp-script"],
        [".generictest", "application/xml"],
        [".gif", "image/gif"],
        [".group", "text/x-ms-group"],
        [".gsm", "audio/x-gsm"],
        [".gtar", "application/x-gtar"],
        [".gz", "application/x-gzip"],
        [".h", "text/plain"],
        [".hdf", "application/x-hdf"],
        [".hdml", "text/x-hdml"],
        [".hhc", "application/x-oleobject"],
        [".hhk", "application/octet-stream"],
        [".hhp", "application/octet-stream"],
        [".hlp", "application/winhlp"],
        [".hpp", "text/plain"],
        [".hqx", "application/mac-binhex40"],
        [".hta", "application/hta"],
        [".htc", "text/x-component"],
        [".htm", "text/html"],
        [".html", "text/html"],
        [".htt", "text/webviewhtml"],
        [".hxa", "application/xml"],
        [".hxc", "application/xml"],
        [".hxd", "application/octet-stream"],
        [".hxe", "application/xml"],
        [".hxf", "application/xml"],
        [".hxh", "application/octet-stream"],
        [".hxi", "application/octet-stream"],
        [".hxk", "application/xml"],
        [".hxq", "application/octet-stream"],
        [".hxr", "application/octet-stream"],
        [".hxs", "application/octet-stream"],
        [".hxt", "text/html"],
        [".hxv", "application/xml"],
        [".hxw", "application/octet-stream"],
        [".hxx", "text/plain"],
        [".i", "text/plain"],
        [".ico", "image/x-icon"],
        [".ics", "application/octet-stream"],
        [".idl", "text/plain"],
        [".ief", "image/ief"],
        [".iii", "application/x-iphone"],
        [".inc", "text/plain"],
        [".inf", "application/octet-stream"],
        [".inl", "text/plain"],
        [".ins", "application/x-internet-signup"],
        [".ipa", "application/x-itunes-ipa"],
        [".ipg", "application/x-itunes-ipg"],
        [".ipproj", "text/plain"],
        [".ipsw", "application/x-itunes-ipsw"],
        [".iqy", "text/x-ms-iqy"],
        [".isp", "application/x-internet-signup"],
        [".ite", "application/x-itunes-ite"],
        [".itlp", "application/x-itunes-itlp"],
        [".itms", "application/x-itunes-itms"],
        [".itpc", "application/x-itunes-itpc"],
        [".IVF", "video/x-ivf"],
        [".jar", "application/java-archive"],
        [".java", "application/octet-stream"],
        [".jck", "application/liquidmotion"],
        [".jcz", "application/liquidmotion"],
        [".jfif", "image/pjpeg"],
        [".jnlp", "application/x-java-jnlp-file"],
        [".jpb", "application/octet-stream"],
        [".jpe", "image/jpeg"],
        [".jpeg", "image/jpeg"],
        [".jpg", "image/jpeg"],
        [".js", "application/x-javascript"],
        [".json", "application/json"],
        [".jsx", "text/jscript"],
        [".jsxbin", "text/plain"],
        [".latex", "application/x-latex"],
        [".library-ms", "application/windows-library+xml"],
        [".lit", "application/x-ms-reader"],
        [".loadtest", "application/xml"],
        [".lpk", "application/octet-stream"],
        [".lsf", "video/x-la-asf"],
        [".lst", "text/plain"],
        [".lsx", "video/x-la-asf"],
        [".lzh", "application/octet-stream"],
        [".m13", "application/x-msmediaview"],
        [".m14", "application/x-msmediaview"],
        [".m1v", "video/mpeg"],
        [".m2t", "video/vnd.dlna.mpeg-tts"],
        [".m2ts", "video/vnd.dlna.mpeg-tts"],
        [".m2v", "video/mpeg"],
        [".m3u", "audio/x-mpegurl"],
        [".m3u8", "audio/x-mpegurl"],
        [".m4a", "audio/m4a"],
        [".m4b", "audio/m4b"],
        [".m4p", "audio/m4p"],
        [".m4r", "audio/x-m4r"],
        [".m4v", "video/x-m4v"],
        [".mac", "image/x-macpaint"],
        [".mak", "text/plain"],
        [".man", "application/x-troff-man"],
        [".manifest", "application/x-ms-manifest"],
        [".map", "text/plain"],
        [".master", "application/xml"],
        [".mda", "application/msaccess"],
        [".mdb", "application/x-msaccess"],
        [".mde", "application/msaccess"],
        [".mdp", "application/octet-stream"],
        [".me", "application/x-troff-me"],
        [".mfp", "application/x-shockwave-flash"],
        [".mht", "message/rfc822"],
        [".mhtml", "message/rfc822"],
        [".mid", "audio/mid"],
        [".midi", "audio/mid"],
        [".mix", "application/octet-stream"],
        [".mk", "text/plain"],
        [".mmf", "application/x-smaf"],
        [".mno", "text/xml"],
        [".mny", "application/x-msmoney"],
        [".mod", "video/mpeg"],
        [".mov", "video/quicktime"],
        [".movie", "video/x-sgi-movie"],
        [".mp2", "video/mpeg"],
        [".mp2v", "video/mpeg"],
        [".mp3", "audio/mpeg"],
        [".mp4", "video/mp4"],
        [".mp4v", "video/mp4"],
        [".mpa", "video/mpeg"],
        [".mpe", "video/mpeg"],
        [".mpeg", "video/mpeg"],
        [".mpf", "application/vnd.ms-mediapackage"],
        [".mpg", "video/mpeg"],
        [".mpp", "application/vnd.ms-project"],
        [".mpv2", "video/mpeg"],
        [".mqv", "video/quicktime"],
        [".ms", "application/x-troff-ms"],
        [".msi", "application/octet-stream"],
        [".mso", "application/octet-stream"],
        [".mts", "video/vnd.dlna.mpeg-tts"],
        [".mtx", "application/xml"],
        [".mvb", "application/x-msmediaview"],
        [".mvc", "application/x-miva-compiled"],
        [".mxp", "application/x-mmxp"],
        [".nc", "application/x-netcdf"],
        [".nsc", "video/x-ms-asf"],
        [".nws", "message/rfc822"],
        [".ocx", "application/octet-stream"],
        [".oda", "application/oda"],
        [".odc", "text/x-ms-odc"],
        [".odh", "text/plain"],
        [".odl", "text/plain"],
        [".odp", "application/vnd.oasis.opendocument.presentation"],
        [".ods", "application/oleobject"],
        [".odt", "application/vnd.oasis.opendocument.text"],
        [".one", "application/onenote"],
        [".onea", "application/onenote"],
        [".onepkg", "application/onenote"],
        [".onetmp", "application/onenote"],
        [".onetoc", "application/onenote"],
        [".onetoc2", "application/onenote"],
        [".orderedtest", "application/xml"],
        [".osdx", "application/opensearchdescription+xml"],
        [".p10", "application/pkcs10"],
        [".p12", "application/x-pkcs12"],
        [".p7b", "application/x-pkcs7-certificates"],
        [".p7c", "application/pkcs7-mime"],
        [".p7m", "application/pkcs7-mime"],
        [".p7r", "application/x-pkcs7-certreqresp"],
        [".p7s", "application/pkcs7-signature"],
        [".pbm", "image/x-portable-bitmap"],
        [".pcast", "application/x-podcast"],
        [".pct", "image/pict"],
        [".pcx", "application/octet-stream"],
        [".pcz", "application/octet-stream"],
        [".pdf", "application/pdf"],
        [".pfb", "application/octet-stream"],
        [".pfm", "application/octet-stream"],
        [".pfx", "application/x-pkcs12"],
        [".pgm", "image/x-portable-graymap"],
        [".pic", "image/pict"],
        [".pict", "image/pict"],
        [".pkgdef", "text/plain"],
        [".pkgundef", "text/plain"],
        [".pko", "application/vnd.ms-pki.pko"],
        [".pls", "audio/scpls"],
        [".pma", "application/x-perfmon"],
        [".pmc", "application/x-perfmon"],
        [".pml", "application/x-perfmon"],
        [".pmr", "application/x-perfmon"],
        [".pmw", "application/x-perfmon"],
        [".png", "image/png"],
        [".pnm", "image/x-portable-anymap"],
        [".pnt", "image/x-macpaint"],
        [".pntg", "image/x-macpaint"],
        [".pnz", "image/png"],
        [".pot", "application/vnd.ms-powerpoint"],
        [".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12"],
        [".potx", "application/vnd.openxmlformats-officedocument.presentationml.template"],
        [".ppa", "application/vnd.ms-powerpoint"],
        [".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12"],
        [".ppm", "image/x-portable-pixmap"],
        [".pps", "application/vnd.ms-powerpoint"],
        [".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12"],
        [".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow"],
        [".ppt", "application/vnd.ms-powerpoint"],
        [".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12"],
        [".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"],
        [".prf", "application/pics-rules"],
        [".prm", "application/octet-stream"],
        [".prx", "application/octet-stream"],
        [".ps", "application/postscript"],
        [".psc1", "application/PowerShell"],
        [".psd", "application/octet-stream"],
        [".psess", "application/xml"],
        [".psm", "application/octet-stream"],
        [".psp", "application/octet-stream"],
        [".pub", "application/x-mspublisher"],
        [".pwz", "application/vnd.ms-powerpoint"],
        [".qht", "text/x-html-insertion"],
        [".qhtm", "text/x-html-insertion"],
        [".qt", "video/quicktime"],
        [".qti", "image/x-quicktime"],
        [".qtif", "image/x-quicktime"],
        [".qtl", "application/x-quicktimeplayer"],
        [".qxd", "application/octet-stream"],
        [".ra", "audio/x-pn-realaudio"],
        [".ram", "audio/x-pn-realaudio"],
        [".rar", "application/octet-stream"],
        [".ras", "image/x-cmu-raster"],
        [".rat", "application/rat-file"],
        [".rc", "text/plain"],
        [".rc2", "text/plain"],
        [".rct", "text/plain"],
        [".rdlc", "application/xml"],
        [".resx", "application/xml"],
        [".rf", "image/vnd.rn-realflash"],
        [".rgb", "image/x-rgb"],
        [".rgs", "text/plain"],
        [".rm", "application/vnd.rn-realmedia"],
        [".rmi", "audio/mid"],
        [".rmp", "application/vnd.rn-rn_music_package"],
        [".roff", "application/x-troff"],
        [".rpm", "audio/x-pn-realaudio-plugin"],
        [".rqy", "text/x-ms-rqy"],
        [".rtf", "application/rtf"],
        [".rtx", "text/richtext"],
        [".ruleset", "application/xml"],
        [".s", "text/plain"],
        [".safariextz", "application/x-safari-safariextz"],
        [".scd", "application/x-msschedule"],
        [".sct", "text/scriptlet"],
        [".sd2", "audio/x-sd2"],
        [".sdp", "application/sdp"],
        [".sea", "application/octet-stream"],
        [".searchConnector-ms", "application/windows-search-connector+xml"],
        [".setpay", "application/set-payment-initiation"],
        [".setreg", "application/set-registration-initiation"],
        [".settings", "application/xml"],
        [".sgimb", "application/x-sgimb"],
        [".sgml", "text/sgml"],
        [".sh", "application/x-sh"],
        [".shar", "application/x-shar"],
        [".shtml", "text/html"],
        [".sit", "application/x-stuffit"],
        [".sitemap", "application/xml"],
        [".skin", "application/xml"],
        [".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12"],
        [".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide"],
        [".slk", "application/vnd.ms-excel"],
        [".sln", "text/plain"],
        [".slupkg-ms", "application/x-ms-license"],
        [".smd", "audio/x-smd"],
        [".smi", "application/octet-stream"],
        [".smx", "audio/x-smd"],
        [".smz", "audio/x-smd"],
        [".snd", "audio/basic"],
        [".snippet", "application/xml"],
        [".snp", "application/octet-stream"],
        [".sol", "text/plain"],
        [".sor", "text/plain"],
        [".spc", "application/x-pkcs7-certificates"],
        [".spl", "application/futuresplash"],
        [".src", "application/x-wais-source"],
        [".srf", "text/plain"],
        [".SSISDeploymentManifest", "text/xml"],
        [".ssm", "application/streamingmedia"],
        [".sst", "application/vnd.ms-pki.certstore"],
        [".stl", "application/vnd.ms-pki.stl"],
        [".sv4cpio", "application/x-sv4cpio"],
        [".sv4crc", "application/x-sv4crc"],
        [".svc", "application/xml"],
        [".swf", "application/x-shockwave-flash"],
        [".t", "application/x-troff"],
        [".tar", "application/x-tar"],
        [".tcl", "application/x-tcl"],
        [".testrunconfig", "application/xml"],
        [".testsettings", "application/xml"],
        [".tex", "application/x-tex"],
        [".texi", "application/x-texinfo"],
        [".texinfo", "application/x-texinfo"],
        [".tgz", "application/x-compressed"],
        [".thmx", "application/vnd.ms-officetheme"],
        [".thn", "application/octet-stream"],
        [".tif", "image/tiff"],
        [".tiff", "image/tiff"],
        [".tlh", "text/plain"],
        [".tli", "text/plain"],
        [".toc", "application/octet-stream"],
        [".tr", "application/x-troff"],
        [".trm", "application/x-msterminal"],
        [".trx", "application/xml"],
        [".ts", "video/vnd.dlna.mpeg-tts"],
        [".tsv", "text/tab-separated-values"],
        [".ttf", "application/octet-stream"],
        [".tts", "video/vnd.dlna.mpeg-tts"],
        [".txt", "text/plain"],
        [".u32", "application/octet-stream"],
        [".uls", "text/iuls"],
        [".user", "text/plain"],
        [".ustar", "application/x-ustar"],
        [".vb", "text/plain"],
        [".vbdproj", "text/plain"],
        [".vbk", "video/mpeg"],
        [".vbproj", "text/plain"],
        [".vbs", "text/vbscript"],
        [".vcf", "text/x-vcard"],
        [".vcproj", "Application/xml"],
        [".vcs", "text/plain"],
        [".vcxproj", "Application/xml"],
        [".vddproj", "text/plain"],
        [".vdp", "text/plain"],
        [".vdproj", "text/plain"],
        [".vdx", "application/vnd.ms-visio.viewer"],
        [".vml", "text/xml"],
        [".vscontent", "application/xml"],
        [".vsct", "text/xml"],
        [".vsd", "application/vnd.visio"],
        [".vsi", "application/ms-vsi"],
        [".vsix", "application/vsix"],
        [".vsixlangpack", "text/xml"],
        [".vsixmanifest", "text/xml"],
        [".vsmdi", "application/xml"],
        [".vspscc", "text/plain"],
        [".vss", "application/vnd.visio"],
        [".vsscc", "text/plain"],
        [".vssettings", "text/xml"],
        [".vssscc", "text/plain"],
        [".vst", "application/vnd.visio"],
        [".vstemplate", "text/xml"],
        [".vsto", "application/x-ms-vsto"],
        [".vsw", "application/vnd.visio"],
        [".vsx", "application/vnd.visio"],
        [".vtx", "application/vnd.visio"],
        [".wav", "audio/wav"],
        [".wave", "audio/wav"],
        [".wax", "audio/x-ms-wax"],
        [".wbk", "application/msword"],
        [".wbmp", "image/vnd.wap.wbmp"],
        [".wcm", "application/vnd.ms-works"],
        [".wdb", "application/vnd.ms-works"],
        [".wdp", "image/vnd.ms-photo"],
        [".webarchive", "application/x-safari-webarchive"],
        [".webtest", "application/xml"],
        [".wiq", "application/xml"],
        [".wiz", "application/msword"],
        [".wks", "application/vnd.ms-works"],
        [".WLMP", "application/wlmoviemaker"],
        [".wlpginstall", "application/x-wlpg-detect"],
        [".wlpginstall3", "application/x-wlpg3-detect"],
        [".wm", "video/x-ms-wm"],
        [".wma", "audio/x-ms-wma"],
        [".wmd", "application/x-ms-wmd"],
        [".wmf", "application/x-msmetafile"],
        [".wml", "text/vnd.wap.wml"],
        [".wmlc", "application/vnd.wap.wmlc"],
        [".wmls", "text/vnd.wap.wmlscript"],
        [".wmlsc", "application/vnd.wap.wmlscriptc"],
        [".wmp", "video/x-ms-wmp"],
        [".wmv", "video/x-ms-wmv"],
        [".wmx", "video/x-ms-wmx"],
        [".wmz", "application/x-ms-wmz"],
        [".wpl", "application/vnd.ms-wpl"],
        [".wps", "application/vnd.ms-works"],
        [".wri", "application/x-mswrite"],
        [".wrl", "x-world/x-vrml"],
        [".wrz", "x-world/x-vrml"],
        [".wsc", "text/scriptlet"],
        [".wsdl", "text/xml"],
        [".wvx", "video/x-ms-wvx"],
        [".x", "application/directx"],
        [".xaf", "x-world/x-vrml"],
        [".xaml", "application/xaml+xml"],
        [".xap", "application/x-silverlight-app"],
        [".xbap", "application/x-ms-xbap"],
        [".xbm", "image/x-xbitmap"],
        [".xdr", "text/plain"],
        [".xht", "application/xhtml+xml"],
        [".xhtml", "application/xhtml+xml"],
        [".xla", "application/vnd.ms-excel"],
        [".xlam", "application/vnd.ms-excel.addin.macroEnabled.12"],
        [".xlc", "application/vnd.ms-excel"],
        [".xld", "application/vnd.ms-excel"],
        [".xlk", "application/vnd.ms-excel"],
        [".xll", "application/vnd.ms-excel"],
        [".xlm", "application/vnd.ms-excel"],
        [".xls", "application/vnd.ms-excel"],
        [".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12"],
        [".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12"],
        [".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"],
        [".xlt", "application/vnd.ms-excel"],
        [".xltm", "application/vnd.ms-excel.template.macroEnabled.12"],
        [".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template"],
        [".xlw", "application/vnd.ms-excel"],
        [".xml", "text/xml"],
        [".xmta", "application/xml"],
        [".xof", "x-world/x-vrml"],
        [".XOML", "text/plain"],
        [".xpm", "image/x-xpixmap"],
        [".xps", "application/vnd.ms-xpsdocument"],
        [".xrm-ms", "text/xml"],
        [".xsc", "application/xml"],
        [".xsd", "text/xml"],
        [".xsf", "text/xml"],
        [".xsl", "text/xml"],
        [".xslt", "text/xml"],
        [".xsn", "application/octet-stream"],
        [".xss", "application/xml"],
        [".xtp", "application/octet-stream"],
        [".xwd", "image/x-xwindowdump"],
        [".z", "application/x-compress"],
        [".zip", "application/x-zip-compressed"]
];

// ----------------------- End of Extensions to MIME --------- //

para mí esto está funcionando bien probado en Chrome v72

function down_file(url,name){
var a = $("<a>")
    .attr("href", url)
    .attr("download", name)
    .appendTo("body");
a[0].click();
a.remove();
}

down_file('https://www.useotools.com/uploads/nulogo[1].png','logo.png')

He tenido buenos resultados con el uso de una etiqueta FORM ya que funciona en todas partes y no tiene que crear archivos temporales en el servidor. El método funciona así.

En el lado del cliente (página HTML), crea un formulario invisible como este

<form method="POST" action="/download.php" target="_blank" id="downloadForm">
    <input type="hidden" name="data" id="csv">
</form>

Luego agrega este código Javascript a su botón:

$('#button').click(function() {
     $('#csv').val('---your data---');
     $('#downloadForm').submit();
}

En el lado del servidor tiene el siguiente código PHP download.php:

<?php
header('Content-Type: text/csv');
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename=out.csv');
header('Content-Transfer-Encoding: binary');
header('Connection: Keep-Alive');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . strlen($data));

echo $_REQUEST['data'];
exit();

Incluso puede crear archivos zip de sus datos de esta manera:

<?php

$file = tempnam("tmp", "zip");

$zip = new ZipArchive();
$zip->open($file, ZipArchive::OVERWRITE);
$zip->addFromString('test.csv', $_REQUEST['data']);
$zip->close();

header('Content-Type: application/zip');
header('Content-Length: ' . filesize($file));
header('Content-Disposition: attachment; filename="file.zip"');
readfile($file);
unlink($file); 

¡La mejor parte es que no deja ningún archivo residual en su servidor ya que todo se crea y destruye sobre la marcha!

La respuesta presentada por hitesh el 30 de diciembre de 2013 sí funciona. Solo requiere un poco de ajuste:

El archivo PHP puede llamarse a sí mismo. En otras palabras, simplemente cree un archivo llamado saveAs.php y coloque este código en él ...

        <a href="saveAs.php?file_source=YourDataFile.pdf">Download pdf here</a>

    <?php
        if (isset($_GET['file_source'])) {
            $fullPath = $_GET['file_source'];
            if($fullPath) {
                $fsize = filesize($fullPath);
                $path_parts = pathinfo($fullPath);
                $ext = strtolower($path_parts["extension"]);
                switch ($ext) {
                    case "pdf":
                    header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\""); // use 'attachment' to force a download
                    header("Content-type: application/pdf"); // add here more headers for diff. extensions
                    break;
                    default;
                    header("Content-type: application/octet-stream");
                    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
                }
                if($fsize) {//checking if file size exist
                  header("Content-length: $fsize");
                }
                readfile($fullPath);
                exit;
            }
        }
    ?>

Estas funciones se usan en stacktrace.js :

/**
 * Try XHR methods in order and store XHR factory.
 *
 * @return <Function> XHR function or equivalent
 */
var createXMLHTTPObject = function() {
    var xmlhttp, XMLHttpFactories = [
        function() {
            return new XMLHttpRequest();
        }, function() {
            return new ActiveXObject('Msxml2.XMLHTTP');
        }, function() {
            return new ActiveXObject('Msxml3.XMLHTTP');
        }, function() {
            return new ActiveXObject('Microsoft.XMLHTTP');
        }
    ];
    for (var i = 0; i < XMLHttpFactories.length; i++) {
        try {
            xmlhttp = XMLHttpFactories[i]();
            // Use memoization to cache the factory
            createXMLHTTPObject = XMLHttpFactories[i];
            return xmlhttp;
        } catch (e) {
        }
    }
}

/**
 * @return the text from a given URL
 */
function ajax(url) {
    var req = createXMLHTTPObject();
    if (req) {
        try {
            req.open('GET', url, false);
            req.send(null);
            return req.responseText;
        } catch (e) {
        }
    }
    return '';
}

Le sugiero que use el evento mousedown, que se llama ANTES del evento click. De esa manera, el navegador maneja el evento click de forma natural, lo que evita cualquier rareza en el código:

(function ($) {


    // with this solution, the browser handles the download link naturally (tested in chrome and firefox)
    $(document).ready(function () {

        var url = '/private/downloads/myfile123.pdf';
        $("a#someID").on('mousedown', function () {
            $(this).attr("href", url);
        });

    });
})(jQuery);

Excelente solución de Corbacho, me acabo de adaptar para deshacerme de la var

function downloadURL(url) {
    if( $('#idown').length ){
        $('#idown').attr('src',url);
    }else{
        $('<iframe>', { id:'idown', src:url }).hide().appendTo('body');
    }
}

Firefox y Chrome probados:

var link = document.createElement('a');
link.download = 'fileName.ext'
link.href = 'http://down.serv/file.ext';

// Because firefox not executing the .click() well
// We need to create mouse event initialization.
var clickEvent = document.createEvent("MouseEvent");
clickEvent.initEvent("click", true, true);

link.dispatchEvent(clickEvent);

Esta es en realidad la solución "Chrome" para Firefox (no lo he probado en otros navegadores, así que por favor deje comentarios sobre la compatibilidad)

Hay tantas cosas pequeñas que pueden suceder al intentar descargar un archivo. La inconsistencia entre los navegadores solo es una pesadilla. Terminé usando esta pequeña biblioteca genial. https://github.com/rndme/download

Lo bueno de esto es que es flexible no solo para las URL sino también para los datos del lado del cliente que desea descargar.

1. cadena de texto
2. text dataURL
3. blob de texto
4. matrices de texto
5. cadena html
6. html blob
7. devolución de llamada ajax
8. archivos binarios

Usando la etiqueta de anclaje y PHP se puede hacer, verifique esta respuesta

Llamada de JQuery Ajax para descargar archivos PDF

HTML
    <a href="www.example.com/download_file.php?file_source=example.pdf">Download pdf here</a>

PHP
<?php
$fullPath = $_GET['fileSource'];
if($fullPath) {
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);
    switch ($ext) {
        case "pdf":
        header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\""); // use 'attachment' to force a download
        header("Content-type: application/pdf"); // add here more headers for diff. extensions
        break;
        default;
        header("Content-type: application/octet-stream");
        header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
    }
    if($fsize) {//checking if file size exist
      header("Content-length: $fsize");
    }
    readfile($fullPath);
    exit;
}
?>

Estoy verificando el tamaño del archivo porque si carga el PDF desde CDN cloudfront, no obtendrá el tamaño del documento que obliga a que el documento se descargue en 0kb. Para evitar esto, estoy verificando con esta condición

 if($fsize) {//checking if file size exist
      header("Content-length: $fsize");
    }

Sé que llego tarde a la fiesta, pero me gustaría compartir mi solución, que es una variación de la solución de Imagine Breaker anterior. Traté de usar su solución, porque su solución me parece más simple y fácil. Pero como dijo otro, no funcionó para algunos navegadores, así que puse alguna variación al usar jquery.

Espero que esto pueda ayudar a alguien por ahí.

function download(url) {
  var link = document.createElement("a");
  $(link).click(function(e) {
    e.preventDefault();
    window.location.href = url;
  });
  $(link).click();
}

Nota: No es compatible con todos los navegadores.

Estaba buscando una manera de descargar un archivo usando jquery sin tener que configurar la url del archivo en el atributo href desde el principio.

jQuery('<a/>', {
    id: 'downloadFile',
    href: 'http://cdn.sstatic.net/Sites/stackoverflow/img/apple-touch-icon@2.png',
    style: 'display:hidden;',
    download: ''
}).appendTo('body');

$("#downloadFile")[0].click();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Uso la solución de @ rakaloof sin JQuery (porque no la necesitas aquí ). ¡Gracias por la idea! Aquí hay una solución basada en formularios de vanillaJS:

const uri = 'https://upload.wikimedia.org/wikipedia/commons/b/bb/Test_ogg_mp3_48kbps.wav';
let form = document.createElement("form");
form.setAttribute('action', uri);
document.body.appendChild(form);
form.submit();
document.body.removeChild(document.body.lastElementChild);