URL.UnsetQuery (gb.web)
Static Function UnsetQuery ( URL As String, Field As String ) As String
Remove the parameter 
Field from a query 
URL and return the new modified query.
If 
URL has no 
Field parameter, the query is returned unmodified.
Examples
Print URL.UnsetQuery("http://mysite.org/test?a=3&b", "a")
Print URL.UnsetQuery("http://mysite.org/test?b", "a")
Print URL.UnsetQuery("http://mysite.org/test?b", "b")