$.fn.watch = function (props, func, interval, id) {
     /// <summary>
     /// Allows you to monitor changes in a specific
     /// CSS property of an element by polling the value.
     /// when the value changes a function is called.
     /// The function called is called in the context
     /// of the selected element (ie. this)
     /// </summary>    
     /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param>    
     /// <param name="func" type="Function">
     /// Function called when the value has changed.
     /// </param>    
     /// <param name="interval" type="Number">
     /// Optional interval for browsers that don't support DOMAttrModified or propertychange events.
     /// Determines the interval used for setInterval calls.
     /// </param>
     /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param>  
     /// <returns type="jQuery" /> 
     if (!interval)
         interval = 100;
     if (!id)
         id = "_watcher";

     return this.each(function () {
         var _t = this;
         var el$ = $(this);
         var fnc = function () { __watcher.call(_t, id) };

         var data = { id: id,
             props: props.split(","),
             vals: [props.split(",").length],
             func: func,
             fnc: fnc,
             origProps: props,
             interval: interval,
             intervalId: null
         };
         // store initial props and values
         $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); });

         el$.data(id, data);

         hookChange(el$, id, data);
     });

     function hookChange(el$, id, data) {
         el$.each(function () {
             var el = $(this);
             if (typeof (el.get(0).onpropertychange) == "object")
                 el.bind("propertychange." + id, data.fnc);
             else if ($.browser.mozilla)
                 el.bind("DOMAttrModified." + id, data.fnc);
             else
                 data.intervalId = setInterval(data.fnc, interval);
         });
     }
     function __watcher(id) {
         var el$ = $(this);
         var w = el$.data(id);
         if (!w) return;
         var _t = this;

         if (!w.func)
             return;

         // must unbind or else unwanted recursion may occur
         el$.unwatch(id);

         var changed = false;
         var i = 0;
         for (i; i < w.props.length; i++) {
             var newVal = el$.css(w.props[i]);
             if (w.vals[i] != newVal) {
                 w.vals[i] = newVal;
                 changed = true;
                 break;
             }
         }
         if (changed)
             w.func.call(_t, w, i);

         // rebind event
         hookChange(el$, id, w);
     }
 }

 $.fn.unwatch = function (id) {
     this.each(function () {
         var el = $(this);
         var data = el.data(id);
         try {
             if (typeof (this.onpropertychange) == "object")
                 el.unbind("propertychange." + id, data.fnc);
             else if ($.browser.mozilla)
                 el.unbind("DOMAttrModified." + id, data.fnc);
             else
                 clearInterval(data.intervalId);
         }
         // ignore if element was already unbound
         catch (e) { }
     });
     return this;
 }