title: Javascript getElementById based on a partial string
body: <p>I need to get the ID of an element but the value is dynamic with only the beginning of it is the same always. </p>
  
  <p>Heres a snippet of the code.</p>
  
  <pre><code>&lt;form class="form-poll" id="poll-1225962377536" action="/cs/Satellite"&gt;
  </code></pre>
  
  <p>The ID always starts with <code>poll-</code> then the numbers are dynamic.</p>
  
  <p>How can I get the ID using just JavaScript and not jQuery?</p>