Seems to me that a lot of really good and obscure Javascript conventions
move through this site on a weekly basis. It would be nice to capture and
index these to create a general JS resource repsository we can reference.
This ideally should be stored at the dynAPI home page.
Personally, I will be willing to "accumulate and forward" solid JS
information to someone, somewhere just let me know. Or, better yet we
should create a "JS Tidbits" submission form at the homepage. Then anyone
can post idea pick-up to this area. Any database megamen looking for a
"mini-project"?
Ray
Take this recent input from David for example..., nice to know. Hard to
find out
----- Original Message -----
From: "David Cushman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, February 26, 2001 3:11 PM
Subject: [Dynapi-Help] Use of setTimeout and setInterval Impact on animation
> Greetings All,
> I have been working a lot with images and
> animations. I have noticed quite a few problems, but
> the following was really puzzling me. The display
> time (animation rate) differences between browsers.
> In researching this I discoverd (and verified) the
> following:
> setTimeout and setInterval have a minimum floor and
> behave differently in different operating
> systems/browsers.
>
> Operating systems and minimum time slice:
> win9x and winME 55ms minimum
> NT and win2k 10ms minimum
>
> Then, to add to the problem, the different browsers
> behave differently.
>
> setTimeout breaks in all browsers at multiples of the
> system minimum. ie if you are using
> win98, settings of
> 1-55 = 55ms approx.
> 56-110 = 110ms approx.
> 111-165 = 165ms approx.
> 166-220 = 220ms approx.
> and so on by increments of the minimum timeslice (55
> here)
>
> setInterval behaves differently based on the browser.
> all browsers at less than the system minimum (using
> win9x 55ms for examples)
> 0-55 = 55ms approx.
> IE again follows the increment of system minimum for
> all values as in the setTimeout example
> ns4 and ns6 above the system minimum will fairly
> closely fall on the desired setting
> 66ms = 66ms approx. and so on.
>
> It is possible to use a multithread technique to
> reduce the win9x timing to around 37ms (still testing
> this).
>
> What does it mean? If you are using setInterval or
> setTimeout in your code or using any of the animation
> widgets, setting a value below 55 ms is pointless for
> win9x (majority of users I believe).
>
> I have seen a lot of code written in DynAPI with
> setTimeout values below 55, this may affect how the
> code operates under NT as opposed to win9x. A setting
> of 10 that defaults to 55ms may work well under win9x,
> but when run under NT or win2K it may be too fast.
>
> Animation in DynAPI
> The majority of the animation widgets use thread as
> the basis for the timing. Thread uses setInterval
> which behaves differently under ns vs ie (see above)
> when above the system minimum (55ms). This results in
> major differences between the animation sequences if a
> setting above 55 is used. For example: a setting of
> 75 will run at 75 under NS but will default to 110
> under IE. This number is the setting you apply to
> .sleep() when using the widgets. Just for general
> information, the default setting for .sleep() in
> thread is 50ms.
>
> I have some test pages that I got from other sources
> that I have been using to run tests to verify this.
> If anyone is interested, I will post them. I would
> like to hear from anyone interested in running the
> same tests on mac and under different browsers
> (opera?). I am also working on a beta of thread that
> uses multithreading techniques for individual
> animations, the goal, a smoother animation. Not sure
> this will work though.
>
> Another thought is that we change thread to use a
> series of numbers instead of the timing value itself.
> Then a new routine in thread could check the operating
> system/browser and assign a preset number based on
> this lookup. Unfortunately it would have to default
> to the values of the worst system, IEunder win9x
> (increments of 55). This would impact the playback
> under NN/win9x, but would give us a consistant
> animation across browsers. Isn't this what DynAPI is
> all about?
> Comments?
>
> one final interesting note, the tests under NN6 took
> twice as long to complete but gave the same timed
> results. I speculate that NN6 is somehow evaluating
> the code once before running it? Anybody have any
> ideas or facts on this? This really impacts any
> animation done in DynAPI when displayed under NN6
> (yes, I know it is not supported yet).
>
> Cheers,
> Dave C. "You Changed What?!?"
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