var hwImage;

	function openWindow(url, w, h) {
		var q = 1;
		w += 20;
		h += 20;
		if (w > (screen.width - 50)) {
			q = (screen.width-50) / w;
			w *= q;
			h *= q;
		}
		
		if (h > (screen.height - 50)) {
			q = (screen.height-50) / h;
			h*=q;
			w*=q;
		}
		
		l = (screen.width-w) / 2;
		t = (screen.height-h) / 2;
		if (hwImage) {
			hwImage.close();
		}
			
		hwImage = window.open(url, 'image', 'left='+l+',top='+t+',width='+w+',height='+h+',scrollbars=yes,resizable=yes')
		hwImage.focus();
		
	}