Como @jAndy mencionó, no hay un código JavaScript adecuado para detectar que se está cerrando una ventana. Partí de lo que @Syno había propuesto.
Pasé por una situación como esa y si sigues estos pasos, podrás detectarlo.
Lo probé en Chrome 67+ y Firefox 61+.
var wrapper = function () { //ignore this
var closing_window = false;
$(window).on('focus', function () {
closing_window = false;
//if the user interacts with the window, then the window is not being
//closed
});
$(window).on('blur', function () {
closing_window = true;
if (!document.hidden) { //when the window is being minimized
closing_window = false;
}
$(window).on('resize', function (e) { //when the window is being maximized
closing_window = false;
});
$(window).off('resize'); //avoid multiple listening
});
$('html').on('mouseleave', function () {
closing_window = true;
//if the user is leaving html, we have more reasons to believe that he's
//leaving or thinking about closing the window
});
$('html').on('mouseenter', function () {
closing_window = false;
//if the user's mouse its on the page, it means you don't need to logout
//them, didn't it?
});
$(document).on('keydown', function (e) {
if (e.keyCode == 91 || e.keyCode == 18) {
closing_window = false; //shortcuts for ALT+TAB and Window key
}
if (e.keyCode == 116 || (e.ctrlKey && e.keyCode == 82)) {
closing_window = false; //shortcuts for F5 and CTRL+F5 and CTRL+R
}
});
// Prevent logout when clicking in a hiperlink
$(document).on("click", "a", function () {
closing_window = false;
});
// Prevent logout when clicking in a button (if these buttons rediret to some page)
$(document).on("click", "button", function () {
closing_window = false;
});
// Prevent logout when submiting
$(document).on("submit", "form", function () {
closing_window = false;
});
// Prevent logout when submiting
$(document).on("click", "input[type=submit]", function () {
closing_window = false;
});
var toDoWhenClosing = function() {
//write a code here likes a user logout, example:
//$.ajax({
// url: '/MyController/MyLogOutAction',
// async: false,
// data: {
// },
// error: function () {
// },
// success: function (data) {
// },
//});
};
window.onbeforeunload = function () {
if (closing_window) {
toDoWhenClosing();
}
};
};