throttle.js

/**
* Calls last function passed in after {timout} ms 
* from last passed function
* usefull for expensive typeahead and searches
*/
var throttle = function(timeout){
  var lastCalled;
  var lastFn;
  var checking = false;

  return function(fn){
    lastCalled = +new Date();
    lastFn = fn;
    if (!checking){
      checking = true;
      var check = function(){
        if (lastCalled + timeout < +new Date()){
          lastFn();
          checking = false;
        } else {
          setTimeout(function(){ check(); }, timeout);
        }
      };
      setTimeout(function(){ check(); }, timeout);
    }
  }
};