title: Injected scripts not firing for Google results pages
body: <p>As a newbie to Safari Extensions I have what I am sure is a terribly trivial question ... </p>
  
  <p>Here goes: I'm building an extension to work with some search engines. To cut a long story short I have boiled my issue down to its simplest form. I have an injected script (an end script). This fires as planned on the Google homepage. But when I enter a query to Google the script does not fire when the subsequent results page loads. </p>
  
  <p>For example, to keep things really basic for testing I created a simple script that just writes to the console; I've set the access level to All so that it fires for all pages. I can see the console message when I open the Google homepage but I dont see it when the subsequent results pages load.</p>
  
  <p>For all intents and purposes it seems as if the transition from Google homepage to results page is not a normal one (that is, not a conventional page load) and does not cause injected scripts to fire. I've only seen this problem on Google so I assume it is something to do with their page loading mechanism. I've tried it with Google Instant on and off and both produce the same behaviour.
  e
  It's one of those problems that seems so basic as to be stupefying! Please help.</p>