Missing wait() function in JavaScript

[Tim Streater]

Anyone know whey a wait() function is not provided in JS? Or why the
function name passed to setTimeout() is a string? That's a real pain in
the neck for me in my application.

What would be really nice would be wait(semaphore) matched by
event(semaphore ), such that setting the event cancelled the wait.

-- tim

[Michael Winter]

Re: Missing wait() function in JavaScript

On 22/06/2005 11:43, Tim Streater wrote:
[color=blue]
> Anyone know whey a wait() function is not provided in JS?[/color]

In a browser environment, it would be a bad thing: scripts usually run
in the GUI thread, so waiting would freeze the application.
[color=blue]
> Or why the function name passed to setTimeout() is a string?[/color]

It's not. In many cases, it can also be a function reference. However,
older implementations will only support string arguments. See
<URL:http://www.jibbering.c om/faq/faq_notes/misc.html#mtSet TI>.

[snip]

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

[Tim Streater]

Re: Missing wait() function in JavaScript

In article <Dsbue.54481$G8 .18035@text.new s.blueyonder.co .uk>,
Michael Winter <m.winter@bluey onder.co.invali d> wrote:
[color=blue]
> On 22/06/2005 11:43, Tim Streater wrote:
>[color=green]
> > Anyone know whey a wait() function is not provided in JS?[/color]
>
> In a browser environment, it would be a bad thing: scripts usually run
> in the GUI thread, so waiting would freeze the application.[/color]

Except that, the browser itself is threaded, surely? E.g. in Safari when
I start it I load 6 or 7 tabs which appear to load asynchronously. If so
then I would have thought it relatively easy to give access to the
threads and the wait/event mechanism. This is going to be more efficient
since it would mean that my waiting function can resume immediately
instead of waiting for the next timeout (although evidently 50ms is not
much :-)
[color=blue][color=green]
> > Or why the function name passed to setTimeout() is a string?[/color]
>
> It's not. In many cases, it can also be a function reference. However,
> older implementations will only support string arguments. See
> <URL:http://www.jibbering.c om/faq/faq_notes/misc.html#mtSet TI>.[/color]

Thanks for this pointer.

Cheers,

-- tim

[Michael Winter]

Re: Missing wait() function in JavaScript

On 22/06/2005 12:33, Tim Streater wrote:
[color=blue]
> In article <Dsbue.54481$G8 .18035@text.new s.blueyonder.co .uk>,
> Michael Winter <m.winter@bluey onder.co.invali d> wrote:[/color]

[snip]
[color=blue][color=green]
>> In a browser environment, [wait()] would be a bad thing: scripts
>> usually run in the GUI thread [...][/color]
>
> Except that, the browser itself is threaded, surely?[/color]

Of course, but it is usually just server requests and other I/O
operations that are threaded. UI updates will be performed by a central
thread and, as scripts often have a direct affect on presentation and
content, they will be executed in that same thread.

A very simple demonstration is to include an alert function call in a
script in the HEAD element of the document, or part the way through the
BODY element. You should immediately notice that rendering stops until
that dialog box is dismissed.

[snip]

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.