var win = null;
function pop_win(url,title,x,y)
{
LeftPosition = (screen.width) ? (screen.width-x)/2 : 0;
TopPosition = (screen.height) ? (screen.height-y)/2 : 0;
win=window.open(url, title, 'toolbar=0,status=0,location=0,directories=0,menubar=0,resizable=1,scrollbars=1,width=' + x + ',height=' + y + ',top='+TopPosition+',left='+LeftPosition);
}