Hi,

I have a PHP site which is directly accessed by index.php?task=whatever. Ajax routines are similar, but are accessed by ajax.php?task=whatever.

I would like to determine where my script is taking a long time.

I could use "Run Profiler" for the first entry location, but cannot seem to browser to another page and run profiler on that server call, or run it on an ajax server call.

How do I do so? Thank you

If you enable Debug Session feature, all related http requests will be profiled and/or debugged depending on initial function you invoke. Under "related" we understand requests that issue the cookies obtained from original request.
For example -- if you open two instance of browser using Windows Explorer, their requests will be unrelated, but if you open one window from another -- they will be certainly related.
Depending on ajax internals, the requests may be related and may be not. You can check $_COOKIE['DBGSESSID'] content to make sure it is a) set and b) contains p=1 flag, like this: DBGSESSID=1@localhost;p=1
Then the profiler resupts will be accessible with [<-] [->] arrows.