function popup(mit,windowW,windowH)
    {  
	// set the screen position where the popup should appear
	var windowX = (screen.width/2)-(windowW/2);
	var windowY = (screen.height/2)-(windowH/2);
	var	windowFeatures = 'titlebar=no,toolbar=no,location=no,directories=no,menubar=no,scrollbars=no,status=no,resizable=0,width='+windowW+',height='+windowH+',left='+windowX+',top='+windowY+',screenX='+windowX+',screenY='+windowY;
	new_window = window.open(mit,"displayWindow", windowFeatures);
	}