JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://dl.dropbox.com/u/786375/watch/watch.js"></script>
<input type="button" id="button" value="obj.cont++"/>

JavaScript

$(function(){

    var obj = {cont: 0};
    
    obj.watch("cont", function(){
        alert("obj.cont = "+obj.cont);
    });
    
    $("#button").click(function(){
        obj.cont++;
    });
});