title: jquery selector with a class and variable id
body: <p>I have an element id in an variable say <code>elementId</code>. Now i want to select the element from a class say <code>.control-menu</code> which have an id equal to element id.</p>
  
  <p>I am trying it like </p>
  
  <pre><code>$('.control-menu "#"+elementId')
  </code></pre>
  
  <p>I am getting syntax error. can someone tell me the right way to do this?</p>