Cómo hacerlo sin JavaScript en línea
generalmente se recomienda evitar JavaScript en línea, pero rara vez hay un ejemplo de cómo hacerlo.
Aquí está mi forma de adjuntar eventos a los botones.
No estoy completamente satisfecho con cuánto tiempo más se compara el método recomendado con un onClickatributo simple .
Solo navegadores 2014
<button class="btn">Button</button>
<script>
let OnEvent = (doc) => {
return {
on: (event, className, callback) => {
doc.addEventListener('click', (event)=>{
if(!event.target.classList.contains(className)) return;
callback.call(event.target, event);
}, false);
}
}
};
OnEvent(document).on('click', 'btn', function (e) {
window.console.log(this, e);
});
</script>
Solo navegadores 2013
<!DOCTYPE html>
<html>
<head>
<script>
(function(doc){
var hasClass = function(el,className) {
return el.classList.contains(className);
}
doc.addEventListener('click', function(e){
if(hasClass(e.target, 'click-me')){
e.preventDefault();
doSomething.call(e.target, e);
}
});
})(document);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script>
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
Navegador cruzado
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
(function(doc){
var cb_addEventListener = function(obj, evt, fnc) {
// W3C model
if (obj.addEventListener) {
obj.addEventListener(evt, fnc, false);
return true;
}
// Microsoft model
else if (obj.attachEvent) {
return obj.attachEvent('on' + evt, fnc);
}
// Browser don't support W3C or MSFT model, go on with traditional
else {
evt = 'on'+evt;
if(typeof obj[evt] === 'function'){
// Object already has a function on traditional
// Let's wrap it with our own function inside another function
fnc = (function(f1,f2){
return function(){
f1.apply(this,arguments);
f2.apply(this,arguments);
}
})(obj[evt], fnc);
}
obj[evt] = fnc;
return true;
}
return false;
};
var hasClass = function(el,className) {
return (' ' + el.className + ' ').indexOf(' ' + className + ' ') > -1;
}
cb_addEventListener(doc, 'click', function(e){
if(hasClass(e.target, 'click-me')){
e.preventDefault ? e.preventDefault() : e.returnValue = false;
doSomething.call(e.target, e);
}
});
})(document);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script type="text/javascript">
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
Cross-browser con jQuery
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
(function($){
$(document).on('click', '.click-me', function(e){
doSomething.call(this, e);
});
})(jQuery);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script type="text/javascript">
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
Puede ejecutar esto antes de que el documento esté listo, hacer clic en los botones funcionará porque adjuntamos el evento al documento.
Aquí hay un jsfiddle
Por alguna extraña razón, la insertHTMLfunción no funciona a pesar de que funciona en todos mis navegadores.
Puede reemplazar siempre insertHTMLcon document.writesi no me importa de inconvenientes
<script>
document.write('<button class="click-me" id="btn1">Button 1</button>');
</script>
Fuentes: