title: How to check "page viewer" to show specific code
body: <p>i make a "pure javascript" web (using HTML5 History API, like Grooveshark or similars), all works ok, but the problem its SEO, especific Facebook &amp; google spiders/tracks.</p>
  
  <p>My idea its to track the "browser" using the PHP vars $_SERVER, and is the "browser" is a specific string, show a diferent HTML (not only the home with the non-executed javascript, AKA no content).</p>
  
  <p>But i have some problems, first, i dont know the "string" of Facebook, Google and another trackers.</p>
  
  <p>Any idea for solve this? (make clasic HTML website not allowed :P)</p>
  
  <p>Thanks</p>