[thelist] XMLHTTP Request Object

Ken Schaefer Ken at adOpenStatic.com
Wed Dec 21 17:24:20 CST 2005

-----Original Message-----
From: thelist-bounces at lists.evolt.org
[mailto:thelist-bounces at lists.evolt.org] On Behalf Of Manektala, Udit
Sent: Thursday, 22 December 2005 8:02 AM
To: thelist at lists.evolt.org
Subject: [thelist] XMLHTTP Request Object

: I finally got the XMLHTTP Request object to work 
: fine right before I read your post. First, wht 
: I did with the XMLHTTP Object was simply to
: load it synchronously, ( turn async flag false ). 
: Any obvious disadvantage to that ??

You can do that. The problem with using XMLHTTP is that it doesn't scale.
Load test your application, and you'll start to see what I posted about in my
blog - you'll get serialization of processing of that page, because XMLHTTP
calls into WinInet under the covers (same as what client applications use),
and WinInet limits itself to two concurrent HTTP connections to each remote

: Turns out that XMLHTTP and ServerXMLHTTP use different stuff 
: inside (URLMON and WinHTTP)

Yes - that's why you should use ServerXMLHTTP. Urlmon is the component that
implements security zones (and a few other things). The main difference from
your point of view would be WinInet -vs- WinHTTP. 

: Oh yeah and do let me know if there are any convincing 
: reasons for using the Async=true mode rather than the 
: Async = false mode.

Really depends on what you're trying to do.

If you were loading a dash-board type application, and you needed the
dashboard to continue loading regardless of the response (or lack of such)
from the remote server, then you could use asynch processing. Effectively you
are handing off the HTTP GET to a background thread so that your current
thread can continue doing whatever else it needs to do (e.g. load the

Sorry I can't help with your timeout issue - seems a pretty generic sort of
error if you ask me...


More information about the thelist mailing list