var rOver=false;
var cached=false;
if (document.images) {
	rOver=true;
	//top images
	studentZoneIcon=new Image;
	studentZoneIcon.src="images/navigation/topNav/student.gif";
	studentZoneOnIcon=new Image;
	studentZoneOnIcon.src="images/navigation/topNav/studentOn.gif";
	
	teachersZoneIcon=new Image;
	teachersZoneIcon.src="images/navigation/topNav/teachers.gif";
	teachersZoneOnIcon=new Image;
	teachersZoneOnIcon.src="images/navigation/topNav/teachersOn.gif";

	cached=true;
}