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 17:03:06 -0500
Message-ID: <443AD61A.30804@mit.edu>
To: Sjoerd Visscher <sjoerd@w3future.com>
CC: public-webapi@w3.org

Sjoerd Visscher wrote:
> So, an *asynchronous* XMLHttpRequest does not block the running javascript
> thread. 

Correct.

> But a *synchronous* call does block the running javascript thread, and 
> no redraws happen in between.

The statement after the comma is false.

> I don't think you can simply "fix" this, because you'll break the single-threadedness of javascript.

Single-threadedness and non-reentrancy are not the same thing, fwiw.

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

Firefox certainly redraws during synchronous XMLHttpRequest calls.

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

Again, everything in Firefox runs on a single thread.  "Redraws" (which you 
never defined) can happen (or at least both layout and painting can happen) 
between the mouseup and click events.

-Boris
Received on Monday, 10 April 2006 22:03:17 GMT

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