title: Get child of element by attribute value
body: <p>I have a jQuery object representing a DIV:</p>
  
  <pre><code>$rel = $('#rel_'+rel.id);
  </code></pre>
  
  <p>In that DIV, there is a BUTTON with my custom attribute "rid" set to rel.id</p>
  
  <p>I need to select that button, it works like this:</p>
  
  <pre><code>$("[rid='"+rel.id+"']").html();
  </code></pre>
  
  <p>But I think that's not the fastest possible solution as it needs to parse the whole DOM for that and because I know the button is always inside the DIV, I could avoid that.</p>
  
  <p>I tried it with the following code:</p>
  
  <pre><code>$rel.children("[rid='"+rel.id+"']").html();
  </code></pre>
  
  <p>but that didn't work.</p>
  
  <p>Thanks for any help.</p>