function centerpopup(Scrol,url){
 var obj = url;
if (document.all) { 
   var w = screen.availWidth;
   var h = screen.availHeight;
}
else if (document.layers) {
   var w = screen.availWidth;
   var h = screen.availHeight;
}

var popW = 400, popH = 400;
var leftPos = (w-popW)/2, topPos = (h-popH)/2;

newWindow = window.open(obj,name,'scrollbars='+ Scrol +',width=' + popW + ',height='+popH+',top='+topPos+',left='+leftPos + 'menubar=no; location=no; toolbar=no');	
newWindow.Focus()
}