Browser.QueryParam("location") won't get you anything if the URL doesn't have a location query - for example
example.com?location=this
Browser.QueryParam("location") would return "this"
For
example.com?anythingelse=this
Browser.QueryParam("location") would return nothing
What you want is the URL of the page you're on, which as detailed in previous messages, isn't actually returned by the browser.url expression