function openNewWindow(url,winName,x,y,opt){

	var xscr=Math.round ((screen.availWidth / 2) - (x / 2));
	var yscr=Math.round ((screen.availHeight / 2) - (y / 2));

	df = window.open(url,winName,'scrollbars=1,width='+x+',height='+y+',top='+yscr+',left='+xscr+opt);
	df.focus();
	return false;
}