var myWindow;
function popOpen(url) {
	var width = 430;
	var height = 430;
	var left = parseInt((screen.availWidth/2) - (width/2));
	var top = parseInt((screen.availHeight/2) - (height/2));
	var windowFeatures = "width=" + width + ",height=" + height +
		",status,resizable,left=" + left + ",top=" + top +
		",screenX=" + left + ",screenY=" + top;
	myWindow = window.open(url, "subWind", windowFeatures);
}
	
// from o'reilly dhtml