jQuery.each在window.onbeforeunload函数中不起作用

Question

I have this code:

HTML:

<div id="wrapper">
    <div>d</div>
    <div>s</div>
    <div>w</div>
</div>

JS:

window.onbeforeunload = function(e) {
    $('#wrapper>div').each(function(k,v) {
        if($(this).text() == 's') {
            return 'aaaa';
        }
    });
}

http://jsfiddle.net/edhvkhg7/2/

When I try to close a chrome tab, the confirm popup does not appear. Why?

Answer 1

You're just returning from the iteration function, not from the beforeunload handler. The only thing jQuery does with the return value of the function is test whether it's false , and stop the iteration. It doesn't get returned from the containing function.

window.onbeforeunload = function(e) {
    var return_val = null;
    $('#wrapper>div').each(function(k,v) {
        if($(this).text() == 's') {
            return_val = 'aaaa';
            return false; // End the loop
        }
    });
    return return_val;
};

Answer 2

window.onbeforeunload = function(e) {
    $('#wrapper>div').each(function(k,v) {
        if($(this).text() == 's') {
            $(this).text('aaaa');
        }
    });
}