Detect which form input has focus using JavaScript or jQuery

Question

How do you detect which form input has focus using JavaScript or jQuery?

From within a function I want to be able to determine which form input has focus. I\'d like

Answer 1

I am not sure if this is the most efficient way, but you could try:

var selectedInput = null;
$(function() {
    $('input, textarea, select').focus(function() {
        selectedInput = this;
    }).blur(function(){
        selectedInput = null;
    });
});

Answer 2

Try

window.getSelection().getRangeAt(0).startContainer

Answer 3

If all you want to do is change the CSS for a particular form field when it gets focus, you could use the CSS ":focus" selector. For compatibility with IE6 which doesn't support this, you could use the IE7 library.