Как вариант...
tmp.html
<!DOCTYPE html>
<html>
<head>
<!--
<script src='http://code.jquery.com/jquery-latest.js'></script>
<link rel='stylesheet type=text/css href=tmp.css' />
-->
<style type='text/css'>
</style>
<script type='text/javascript'>
</script>
</head>
<body>
<script type='text/javascript'>
setTimeout(function (){
loadScript('tmp.js')
},4000);
function loadScript(Url) {
var script = document.createElement('SCRIPT');
script.type = "text/JavaScript";
script.src = Url;
document.getElementsByTagName('head')[0].appendChild(script);
};
</script>
</body>
</html>
tmp.js
google_ad_client='pub-***';
google_alternate_color='FFFFFF';
google_ad_width=336;
google_ad_height=280;
google_ad_format='336x280_as';
google_ad_type='image';
google_ad_channel='9212457***';
google_color_border='#f8f9f2';
google_color_link='#5d5d5d';
google_color_bg='#f8f9f2';
google_color_text='#5d5d5d';
google_color_url='#5d5d5d';
loadScript('http://pagead2.googlesyndication.com/pagead/show_ads.js');