title: Javascript trigger submit button
body: <p>I already tried to googled it but nothing helped me.<br>
  I want to trigger the following button:  </p>
  
  <pre><code>&lt;input class="btn btn_large btn_green" value="Go" type="submit"&gt;
  </code></pre>
  
  <p>If the element would be an id this would work like a charm:  </p>
  
  <pre><code>document.getElementById('btn btn_large btn_green').submit();
  </code></pre>
  
  <p>But since I can't assign an id to this button this isn't working.<br>
  Even if I try to call it via  </p>
  
  <pre><code>document.getElementsByClassName("").submit();
  </code></pre>
  
  <p>it isn't working.  </p>
  
  <p>Thanks in advance</p>