title: How to differentiate between Google Bot visit and Bing Bot visit
body: <p>I am planning to have 2 versions(A/B) of a page. 
  If the visit comes from the Google Bot visit, the response should be the A version 
  or 
  If the visit comes from the Bing Bot visit, the response should be a the B version.
  How do I know if the visit is from the Google Bot or Bing Bot in PHP?</p>
  
  <p>Thanks.</p>