Oh boy, you guys are making a mess of this. When I insert this code in html mode:

 

<script type="text/javascript"><!--
google_ad_client = "pub-8037121247057075";
google_ad_width = 728;
google_ad_height = 90;
google_ad_format = "728x90_as";
google_ad_type = "text_image";
google_ad_channel ="";
//--></script>
<script type="text/javascript"
  src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>

 

click on Normal mode and go back to HTML mode there is nothing, empty.