function showAd(size) {
	var w = size.substr(0, size.indexOf("x"));
	var h = size.substr(size.indexOf("x") + 1);
	var url = "http://www.patricksaviation.com/scripts/display_ad.php?size=" + size;
	var iframe = "<iframe src='" + url + "' marginwidth='0' marginheight='0' hspace='0' vspace='0' frameborder='0' scrolling='no' allowTransparency='true' width='" + w + "' height='" + h + "'></iframe>";
	document.writeln(iframe);
}