Function throttle implementation in JS, with default parameters, using closures.

throttle.js

/* throttle(func,ms,context) returns a function that can't be called more than once every ms milliseconds.
context and ms parameters are optionnal.
*/
var throttle = (function(window){
  var defaultMs=50;
  return function (func,ms,context){
  	var to;
  	var wait=false;
  	return function(){
  	  var args = Array.prototype.slice.call(arguments);
  	  var later = function(){
  		  func.apply(context || window,args);
  	  };
  	  if(!wait)  {
  		  later();
  		  wait = true;
  		  to = setTimeout(function() {
  		    wait = false;
  		  },ms || defaultMs);
  	  }
  	};
  };
})(window);

/*
Usage :
function myMoveHandler(e) {
  // magic here
}
var throttledHandler = throttle(myMoveHandler);
window.addEventListener('mousemove',throttledHandler);
*/