HTTP response time test

I cannot find anything mentioning if Hobbit/Xymon can test how long an
HTTP or HTTPS page takes to respond and alert on that. In other
words, if a site is in a hung state so that it still technically
"responds" but it takes 5 seconds for the page to respond how does
Hobbit/Xymon handle that? I want to make sure that if a site that we
are monitoring takes longer than a couple of seconds to load we are
alerted,

Do any of you do a test like that and how are you doing it?

Thanks, Jason