W3C home > Mailing lists > Public > public-webapi@w3.org > April 2006

Re: Proposal for mousewheel events

From: Boris Zbarsky <bzbarsky@mit.edu>
Date: Mon, 10 Apr 2006 15:46:01 -0500
Message-ID: <443AC409.10508@mit.edu>
To: Sjoerd Visscher <sjoerd@w3future.com>
CC: public-webapi@w3.org

Sjoerd Visscher wrote:
> No, a synchronous XMLHttpRequest does not block the running javascript 
> thread.

I'm not sure what you mean by that, actually.   It block execution of the script 
in which the call was made.

> But it will therefore also not block the onclick handler

It'll block it in Gecko.

> and you'll still see no black background flash.

Did you test this?

> The onclick and onmouseup events run in the same thread. Only when this thread is done, you'll see 
> a redraw. The onreadystate event will start a new thread to finish 
> handling the XMLHttpRequest.

There's no new thread started in Gecko.

> Firefox and IE do not redraw as long as the javascript code is running.

Actually, that's not true; there are ways to force a redraw while JS is running 
(eg setting the value of a form input will often do it).

> So what I mean with forbidding a redraw is that the 2 events run in the 
> same javascript thread.

All JS in Gecko, as far as this discussion is concerned, runs on a single 
thread.  All events fire on that thread.  All painting happens on that thread. 
There is only one thread in the application as far as page code is concerned.

-Boris
Received on Monday, 10 April 2006 20:46:22 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:18:54 GMT