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Re: Shutting script down when leaving page

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On Mon, 27 Jan 2014 10:41:24 +0000, Tim Streater wrote:

> In article <6507961.N3xZG9CObR@PointedEars.de>, Thomas 'PointedEars'
> Lahn <PointedEars@web.de> wrote:
> 
>> Andrew Poulos wrote:
>> 
>> > On 27/01/2014 2:25 PM, Xox wrote:
>> >> Let us suppose I have a page, a.html, which contains a script which
>> >> constantly invokes itself or is invoked -- it's running not
>> >> necessarily continuously but at regular intervals, or maybe it is
>> >> looping.
>> 
>> There are no pages, they are not “running”, and they certainly do not
>> “loop”.  Scripts do not “invoke themselves” either.
>> 
>> Script code may cause other code to be executed repeatedly, using the
>> browser API, and it may cause a resource in a view to be reloaded, upon
>> which it could be executed again if it was part of that resource.  That
>> is not a loop.
> 
> Yet more sneering by PointyHead at people's "incorrect" use of
> terminology. Still, I expect it's how he's used to treating his
> students, if any.
> 
>> > Perhaps calling onunload and/or onbeforeunload and stopping the
>> > script will help.
>> 
>> “onunload” and “onbeforeunload” are event-handler attributes and
>> properties.
>> They cannot be called by the developer to the desired effect because
>> the developer does not know when they should call them in the first
>> place.
>> 
>> There is an unfortunate tendency of saying that something is “called”
>> when any action is caused by anything, particularly among beginners. 
>> People nonsensically speak of “Ajax calls”, for example.
> 
>   var request = new XMLHttpRequest ();
>   ...
>   request.send (data);
> 
> Hmmm, looks like a function call to me.
> 
> If PointyHead were less of an arsehole, he might have simply reassured
> the OP by describing what happens to a page being displayed, and its
> resources, when the user navigates to another page. IOW, behaved like a
> good teacher. But no. Instead, he feels an irresistible urge to demean
> posters by making corrections to their usage of terminology, and their
> manner of posting.

I am sorry my vocabulary offended.  (Although I don't know
what the statelessness of HTTP has to do with anything.)  I
will explain in another way.  I have a page which has some
Javascript functions on/in it.  Some of the functions are
repeatedly called/started/invoked/run by setInterval or setTimeout.
They look to see whether certain objects etc. are present and
where they are, and may move or create other objects accordingly.
There could be a lot of these objects.  The functions could 
thus consume a lot of resources.

Now suppose the browser navigates to another page.  I am
wondering whether some browsers may continue to execute the 
aforesaid function invocations anyway.  I would think not, but 
stranger things have been coded.

I could make a list of the ids returned by setInterval
and run clearInterval against each on the onunload event,
but I'd just as soon not bother if it's superfluous.

Does anyone know?

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Thread

Shutting script down when leaving page Xox <etacx18@etaoin.com> - 2014-01-27 03:25 +0000
  Re: Shutting script down when leaving page Andrew Poulos <ap_prog@hotmail.com> - 2014-01-27 18:08 +1100
    Re: Shutting script down when leaving page "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-01-27 10:23 +0100
    Re: Shutting script down when leaving page Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-27 11:21 +0100
      Re: Shutting script down when leaving page Tim Streater <timstreater@greenbee.net> - 2014-01-27 10:41 +0000
        Re: Shutting script down when leaving page Xox <etacx18@etaoin.com> - 2014-01-27 19:43 +0000
          Re: Shutting script down when leaving page "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-01-27 20:53 +0100
            Re: Shutting script down when leaving page Xox <etacx18@etaoin.com> - 2014-01-27 20:52 +0000
          Re: Shutting script down when leaving page Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-28 01:20 +0100
            Re: Shutting script down when leaving page Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-28 01:24 +0100
            Re: Shutting script down when leaving page "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-01-27 18:44 -0800
            Re: Shutting script down when leaving page Xox <etacx18@etaoin.com> - 2014-01-28 05:03 +0000
              Re: Shutting script down when leaving page Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-28 11:33 +0100
                Re: Shutting script down when leaving page Xox <etacx18@etaoin.com> - 2014-01-28 19:40 +0000
            Re: Shutting script down when leaving page "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-01-28 09:31 +0100
      Re: Shutting script down when leaving page Christoph Michael Becker <cmbecker69@arcor.de> - 2014-01-27 21:37 +0100
        Re: Shutting script down when leaving page Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-28 00:10 +0100
          Re: Shutting script down when leaving page Christoph Michael Becker <cmbecker69@arcor.de> - 2014-01-28 00:54 +0100

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