function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

var preloadFlag = false;
function preloadImages() {

	if (document.images) 
	{
	   img1 = new newImage("../images/home_btn_on.jpg");
	   img2 = new newImage("../images/about_us_btn_on.jpg");
	   img3 = new newImage("../images/contact_us_btn_on.jpg");	
	   img4 = new newImage("../images/site_map_btn_on.jpg");	
	   
	      
	   preloadFlag = true;

	}

}