'onChange' callback delayed until user stops changing value of input

wait_for_it.js

/* Calls callback function if value of given element stops changing

 elem - element which's value we're watching
 callback - anonymous method or callback fuction name
 (delay) - delay before callback 
*/
wait_for_it = function(elem, callback, delay) {
  var old_val;
  if (delay == null) {
    delay = 750;
  }
  old_val = elem.val();
  return setTimeout((function() {
    if (elem.val() === old_val) {
      return callback();
    }
  }), delay);
};

/* Usage example */
$('input').change(function() {
    wait_for_it($(this), function() {
        alert('foo!');
    });
});