Cross-Platform Expander/Collapser Javascript

A groovy cross-platform expander/collapser javascript from Blakems.com. That I find especially usefull for form submission notifications:

HTML:
<input type="submit" name="action" 
       value="Submitting Form"
       onClick="expand('sending')" />
<p id="sending" style="display:none;">
  <strong>Submitting form. Please Wait!</strong>
</p>

Javascript:
function expand() {
  for (var i=0; i<expand.arguments.length; i++) {
    var element = document.getElementById(expand.arguments[i]);
    element.style.display = "block";
  }
}

function collapse() {
  for (var i=0; i<collapse.arguments.length; i++) {
    var element = document.getElementById(collapse.arguments[i]);
    element.style.display = "none";
  }
}