function popupWindow(url,name,width,height) {
	var style="scrollbars = yes, resizable = yes, toolbar = yes, location = no, menubar = no, status = no";

	if (width) {
		if (window.screen.width > width) style += ", left = "+(window.screen.width-width)/2;
		else width = window.screen.width;
		style += ", width = "+width;
	}

	if (height) {
		if (window.screen.height > height) style += ", top = "+(window.screen.height-height)/3;
		else height = window.screen.height;
		style += ", height = "+height;
	}
	window.open(url,name,style);
}