title: jQuery: get all children whose ID contains part of string
body: <p>I have a set of links:</p>
  
  <pre><code>&lt;div id="parent"&gt;
     &lt;a id="UserFirst" href="#"&gt;&lt;/a&gt;
     &lt;a id="UserSecond" href="#"&gt;&lt;/a&gt;
     &lt;a id="UserThird" href="#"&gt;&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I need a quick way of getting (for example) all the <code>a</code> children of <code>#parent</code>, whose ID contains the letter <code>i</code>.</p>
  
  <p>How can I do it?</p>