Question

I was using jQuery live() function to detect when the user was pressing some special keys (arrows, etc.):

$('.TextBox1').live('keydown', function(e) {
    var keyCode = e.keyCode || e.which;
    if (keyCode == 40) {
        e.preventDefault();
        // ...
    }
});

It was working fine for a couple of months when suddenly yesterday it stopped working, preventing every line of JS code below it from executing. I have tried to replace it with the .keyup function but this has not helped. What could have happened?

Answer 1

I assume you’ve updated to the latest version of jQuery? live() has been deprecated since jQ1.7, and is now removed as of 1.9.

Instead, you should use on() with a delegate parameter:

$(document).on('keydown', '.TextBox1', function(e) {
    var keyCode = e.keyCode || e.which;

    if (keyCode == 40) {
        e.preventDefault();
        //...
    }
});

Note that for best performance you should replace document in the above example with the closest parent element of .TextBox1 which is not dynamically appended to the DOM after page load.