Just testing if a paramter is IN the url

[Dan Acuff]

How do I go about testing if a parameter is in the URL, or maybe its length?

I want to do this in a c:when tag.

 <c:when test="#{param['id']}">

Thanks for the help.

Update, the below SHOULD work, but it is not.. can anyone help?

  <c:when test="#{fn:length(param.id) > 0}">
	Do something else...
</c:when>