title: What does ver=3.1.2 at the end of ajax.js or filename.js?ver=3.1.2 mean?
body: <p>I am having some conflicting jquery issues on a website and as I was trying to figure it out, I have noticed the following suffixes in my head files:</p>
  
  <pre><code>ajax.js?ver=3.1.2'&gt;&lt;/script&gt; 
  jquery.prettyPhoto.js?ver=3.1.2'&gt;&lt;/script&gt; 
  jquery.cycle.all.2.72.js?ver=3.1.2'&gt;&lt;/script&gt; 
  jcarousellite_1.0.1.min.js?ver=3.1.2'&gt;&lt;/script&gt; 
  jquery.kwicks-1.5.1.pack.js?ver=3.1.2'&gt;&lt;/script&gt; 
  ddsmoothmenu.js?ver=3.1.2'&gt;&lt;/script&gt; 
  js.js?ver=3.1.2'&gt;&lt;/script&gt; 
  </code></pre>
  
  <p>obviously the 3.1.2 is probably some type of "latest update" or something.  How does it work? How do you synch theme or balance them out?</p>
  
  <p>Would these other files be failing because of mixed versions? Here the rest of it:</p>
  
  <pre><code>.css?ver=20110325' type='text/css' media='all' /&gt; 
  .css?ver=3.1.2' type='text/css' media='all' /&gt; 
  l10n.js?ver=20101110'&gt;&lt;/script&gt; 
  jquery.js?ver=1.4.2'&gt;&lt;/script&gt; 
  all.js?ver=3.1.2#xfbml=1'&gt;&lt;/script&gt; 
  comment-reply.js?ver=20090102'&gt;&lt;/script&gt; 
  </code></pre>
  
  <p>Not sure if this is the way I should post on Stackoverflow so feel free to edit as it should.</p>