function m_win(url,windowname,width,height) {
var features="location=no, menubar=no, status=no, scrollbars=no, resizable=no, toolbar=no";
if (width) {
	if (window.screen.width > width)
		features+=", left="+(window.screen.width-width)/2;
		else width=window.screen.width;
			features+=", width="+width;
		}
		if (height) {
			if (window.screen.height > height)
			features+=", top="+(window.screen.height-height)/2;
		else height=window.screen.height;
			features+=", height="+height;
		}
	window.open(url,windowname,features);
}