title: Javascript clear content of selectbox
body: <p>As part of my populating selectbox function I am clearing the contents of the populated select box and then inserting options to a empty box. Although the select box is not being cleared correctly and a lot of options are not removed. I am using the following code to clear the contents of the select box:</p>
  
  <pre><code>for(var i = 0; i &lt; document.getElementById(selectbox).options.length; i++)
      document.getElementById(selectbox).options[i] = null;
  </code></pre>
  
  <p>Why not all the options are removed from the selectbox?</p>