var app = Class.create();
app.prototype = {	
	initialize : function() {		
		//in the constructor below, the 1st argument must match the literal string of the vaiable; 
		//2nd argument should be left blank   
		browserHistory = new historyStack("browserHistory", "");				
		browserHistory.onBrowserAddressChanged = function(){			
			principal(this.current); //replace with your own logic			
		};
	}
}