title: JavaScript Source Query
body: <p>While browsing the code of some websites I sometimes notice that some JavaScript files are included like this:</p>
  
  <pre><code>  &lt;script type="text/javascript" src="javascripts/jquery.js?1252521516"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>But I don't see what the jquery.js <strong>?1252521516</strong> part of the src parameter does. Can anyone explain this to me please?</p>