Dynamically insert input field to form

Hi quomon people!

How can I, using JavaScript, append form-input-elements to my html-form, to have their values submitted with the form? I have a solution that only works in Firefox so far. Internet Explorer however doesn't recognise these new fields.

I've tried with something like this:

 <script>
  function init(form)
  {
   var input = document.createElement("input");
   
   input.name = "c";
   input.value = "d";
   input.type = "text";
   
   form.appendChild(input);
  }
 </script>

 <form action="test.html" onfocus="init(this)" method="get">
  <input name="a" value="b" type="text"/>
  <input type="submit" />
 </form>

I've also tried to add the elements to the form.elements array but no luck. Even tried using the setAttribute method.

Any ideas / experience with this?