title: Change part of "src" attribute of iframe with jQuery
body: <p>I actually need to disable autoplay on a vimeo iframe embed on a drupal 6 website.</p>
  
  <p>I can't change this settings in the embedmedia module, so I need to use jQuery to do this.</p>
  
  <p>This is the original "src" vimeo content:</p>
  
  <pre><code>&lt;iframe src="http://player.vimeo.com/video/69431566?fullscreen=1&amp;amp;show_title=1&amp;amp;show_byline=0&amp;amp;show_portrait=1&amp;amp;autoplay=1" frameborder="0" style="height: 23vw; width: 100vw;"&gt;&lt;/iframe&gt;
  </code></pre>
  
  <p>I override the height and width attributes with jQuery already.</p>
  
  <p>So I try to do the same for "src" but my code replace the "src" content:</p>
  
  <pre><code>$("#media-vimeo-1 iframe").attr('src','autoplay=0');
  </code></pre>
  
  <p>How can I preserve the other part of src content and only change the autoplay setting ?</p>