if (document.images) {

	img1on = new Image();           
	img1on.src = "images/topbut-comp_b.gif";  
	img2on = new Image();           
	img2on.src = "images/topbut-serv_b.gif";  
	img3on = new Image();           
	img3on.src = "images/topbut-port_b.gif";  
	img4on = new Image();           
	img4on.src = "images/topbut-cont_b.gif";  
	 
	img1off = new Image();          
	img1off.src = "images/topbut-comp_a.gif"; 
	img2off = new Image();          
	img2off.src = "images/topbut-serv_a.gif"; 
	img3off = new Image();          
	img3off.src = "images/topbut-port_a.gif"; 
	img4off = new Image();          
	img4off.src = "images/topbut-cont_a.gif"; 

}
function imgOn(imgName) {
	if (document.images) {
    	document[imgName].src = eval(imgName + "on.src");
    }
}

function imgOff(imgName) {
	if (document.images) {
		document[imgName].src = eval(imgName + "off.src");
	}
}




function popupWindowCenter(myurl,iheight,iwidth) {
	var iMyWidth;
	var iMyHeight;
	var newWindow;
	iMyWidth = (window.screen.width-540) //Far Right.
	iMyHeight = 0 //Top of the Screen
	//iMyWidth = (window.screen.width/2) - ((iwidth/2) + 10); //half the screen width minus half the new window width (plus 5 pixel borders).
	//iMyHeight = (window.screen.height/2) - ((iheight/2) + 50); //half the screen height minus half the new window height (plus title and status bars).
	var win2 = window.open(myurl,"Window2","height="+ iheight +",width="+ iwidth +",left=" + iMyWidth + ",top=" + iMyHeight + ",screenX=" + iMyWidth + ",screenY=" + iMyHeight + ",status=yes,toolbar=no,menubar=no,location=no,scrollbars=yes");
	win2.focus();
}