var OpenWin=null;
var onscreen=false;

function popup(page) {
OpenWin = this.open(page, "CtrlWindow", 'left=50,top=50,toolbar=1,scrollbars=1,status=1,location=1,statusbar=1,menubar=1,resizable=1,width=720,height=550');

OpenWin.focus();
onscreen=true; 
}