Simon Willison’s Weblog

rather baffling finding: POST requests, made via the XMLHTTP object, send header and body data in separate tcp/ip packets [and therefore,] xmlhttp GET performs better when sending small amounts of data than an xmlhttp POST

— Iain Lamb

Posted 18th August 2009 at 12:27 pm

Tagged ajax, get, http, iainlamb, performance, post, xmlhttprequest

5 comments

This quote came up when in a debate about GET v.s. POST in the comments over here - this is the only source I've seen for this information, and it doesn't specify which browsers are affected. At any rate, I don't see this performance benefit being worth using one verb over the other in most cases (since Ajax autocomplete searches use GET already) - but it might have some importance for real-time collaboration applications such as MobWrite.
Simon Willison - 18th August 2009 12:33 - #
Simon, I read that Vitamin link too -- it referred to a Yahoo performance article which said the Yahoo Mail team found this, but there wasn't any further info.

I too feel it doesn't seem worth using just one verb unless there are very specific scenarios...

anup - 18th August 2009 16:27 - #
Sorry -- slight correction -- the Vitamin article didn't say where it got that from. I searched last week for this info and found it here:
http://developer.yahoo.com/performance/rules.html but it didn't really offer any details. The comment you found is probably what the above link refers to...

anup - 18th August 2009 16:39 - #
I was curious about this too, so I ran some of my own tests: http://josephscott.org/archives/2009/08/xmlhttpreq uest-xhr-uses-multiple-packets-for-http-post/

Firefox was the only browser I tested that didn't use 2 packets for XHR over HTTP POST.

Joseph Scott - 27th August 2009 17:03 - #
Hi Simon,

Another link to add is http://yuiblog.com/blog/2007/03/01/performance-res earch-part-3/#comment-59531

Fahed

Fahed - 31st August 2009 13:59 - #