function openwindow(url)
{
var windowW=800;// wide
var windowH=500; // high

var windowX = (screen.width/2)-(windowW/2);
var windowY = (screen.height/2)-(windowH/2);

win2 = window.open(url,"new_window",
"toolbar=yes,location=yes,directories=no,status=yes,menubar=yes,scrollbars=yes,resizable=yes, height=500, width=800")

win2.moveTo(windowX,0);
}