title: JQuery change class by given id's
body: <p>I have a number of tables, for example:</p>
  
  <pre><code>&lt;table class="onion" id="12"&gt;
  </code></pre>
  
  <p>When a div named "Mark_Pre_Val" gets clicked i want tables with the id's 4, 6, 12 &amp; 21
  to change their class to "onionClick", and if one of them is already "onionClick" then don't
  change the class.</p>
  
  <p>Here is the click event:</p>
  
  <pre><code>    $(".Mark_Pre_Val").click(function(){       });
  </code></pre>
  
  <p>Can someone point me to the right direction how to approach this?</p>