jqDebounce.js

(function($) {

    $.extend({
        debounce: function(func, wait, immediate) {
                    var timeout, args, context, timestamp, result;
                
                    var later = function() {
                      var last = _.now() - timestamp;
                
                      if (last < wait && last >= 0) {
                        timeout = setTimeout(later, wait - last);
                      } else {
                        timeout = null;
                        if (!immediate) {
                          result = func.apply(context, args);
                          if (!timeout) context = args = null;
                        }
                      }
                    };
                
                    return function() {
                      context = this;
                      args = arguments;
                      timestamp = _.now();
                      var callNow = immediate && !timeout;
                      if (!timeout) timeout = setTimeout(later, wait);
                      if (callNow) {
                        result = func.apply(context, args);
                        context = args = null;
                      }
                
                      return result;
                    };
                  };
    });
})(jQuery);