title: prevent the regular tab-key function onkeyup
body: <p>I have about 20 small dropdowns in row. Each of those have two javascript functions.</p>
  
  <ul>
  <li><code>onchange</code>: call an ajax function for saving the value</li>
  <li><code>onkeyup</code>: jump to the next dropdown and open it</li>
  </ul>
  
  <p>Now if the user press tab, the next dropdown will be omitted. This is why I want to prevent the regular tab-key function.
  How to do this?</p>