function openwindow(url){
var myLeft = Math.round((screen.availWidth - 600) / 2);
var myTop = Math.round((screen.availHeight - 600) / 2) - 20;
var DIS=window.open(url,"DIS","menubar=0,toolbar=0,location=0,scrollbars=1,resizable=0,width=600,height=600,left="+myLeft+",top="+myTop);
}