title: Onclick doesn't work in userscript
body: <p>there is an element in the page:</p>
  
  <pre><code>&lt;div action="storage" class="item_menu storage_menu ajax_action 
  header_menu_item tc"&gt;Menu&lt;/div&gt;
  </code></pre>
  
  <p>And the idea is to make an alert when somebody clicks on it.
  The code i now use:</p>
  
  <pre><code>document.getElementByClass("storage_menu").onclick = alert("Норм");
  </code></pre>
  
  <p>doesn't work. 
  Could someone please explain what am i doing wrong?</p>