Idiomatic jQuery delayed event (only after a short pause in typing)? (aka timewatch/typewatch/keywatch)

I frequently use the following approach, a simple function to execute a callback, after the user has stopped typing for a specified amount of time::

$(selector).keyup(function () {
  typewatch(function () {
    // executed only 500 ms after the last keyup event.
  }, 500);
});

Implementation:

var typewatch = (function(){
  var timer = 0;
  return function(callback, ms){
    clearTimeout (timer);
    timer = setTimeout(callback, ms);
  };
})();

I think this approach is very simple, and it doesn’t imply any global variables.

For more sophisticated usages, give a look to the jQuery TypeWatch Plugin.