title: Javascript clear multi select boxes
body: <p>I've 2 multiselect boxes one is with values and the second one is empty. When I choose option from the left and click arrow button it takes the value to the second one. My question is how can I clear it by a function in <code>button</code> and restore these values I mean get back the value to the first one and clear the second one. I tried like that but it does not work.</p>
  
  <pre><code>myOptions.options.length = 0;
  myOptions.options[0] = new Option("", "");
  </code></pre>