1: PURPOSE	use the event loop idea, to monitor the data change, currently in front-end world, we get the data from	the back-end ,and show the data , if data change , we need do some action, so the purpose is : design a data	driven framework. the watcher.js is the test for that . 2: HOW TO USE IT?	in the Observer.js, we have the viewModel (which come from the MVVM), so :	//user view Model	var myviewModel={	targetAttr:¡®some value¡¯	};	//start watch	watcher.startWatch();	watcher.watchUtil(¡®targetAttr¡¯,myviewModel,function(){ // this is the user define function, this function will check whether the targetAttr value change return true/false;	}).do(function(){ //if data change, do some action	}); 3: Bugs. watcher.stopWatch() do not work 4: TODO: a: will implement removeWatchTarget method	b: add test report under IE6/7	c: consider the complex senario	d: consider the dependance between watcher, avoid the endless loop