Timeouts and Thread(?) Interruption/Execution

[Gene Wirchenko]

Dear JavaScripters:

Something else that the texts do not seem to cover:

Suppose that I have a form and a timeout. The form has
validation on the fields. If a timeout occurs during the execution of
validation code, what happens?

Is the validation code terminated? Interrupted then resumed
somehow? Executed in parallel with the timeout code?

Or is this undefined?

Sincerely,

Gene Wirchenko

[Richard Cornford]

Gene Wirchenko wrote:
> Dear JavaScripters:
>
> Something else that the texts do not seem to cover:
>
> Suppose that I have a form and a timeout. The form has
> validation on the fields. If a timeout occurs during the execution of
> validation code, what happens?

The timeout waits until the executing code finishes.

> Is the validation code terminated?

No.

> Interrupted then resumed
> somehow?

No.

> Executed in parallel with the timeout code?

In principle, if a web page consisted of a frameset (or embedded
IFRAMEs) so there were multiple ECMAScript global objects (one for each
frame/window) and the timeout was set in one frame/window and the other
code was executing in another then it may be possible for the two to
execute in parallel, but I have not yet seen that possibility
demonstrated in any actual environment
(and I have seen test code that should have been able to demonstrate
that behaviour if it did exist).

> Or is this undefined?

The specification makes no provision for the interruption of executing
code or for parallel execution, and does not provide any of the tools
that would be necessary in order to render doing that 'safe'.

Richard.

[Dr J R Stockton]

In comp.lang.javascript message <n4htc7pvev38hjrea5vhvi9dj4r4u062ff@4ax.
com>, Thu, 24 Nov 2011 14:29:49, Gene Wirchenko <ge...@ocis.net> posted:

> Suppose that I have a form and a timeout. The form has
>validation on the fields. If a timeout occurs during the execution of
>validation code, what happens?

You need to realise that those who initially wrote JavaScript were in a
country that never developed a language of its own, and is where people
often use words with a flagrant disregard for their proper meaning.
Especially in regard to date/time.

"getTimezoneOffset", in JavaScript, means "getTimeOffset".

"timeout" really means "delayed function call".

There is no provision for, in the general sense, interrupting running
script (the script can pause and restart, then looking for new
information (such as STOP!)).

The consequences of the impossible are undefined.

My "validation" page includes a parameter-driven routine for doing most
or all of the validation of a many-field form with a minimum (roughly)
of new code.

--
(c) John Stockton, nr London, UK. ?@merlyn.demon.co.uk Turnpike v6.05.
Website <http://www.merlyn.demon.co.uk/> - w. FAQish topics, links, acronyms
PAS EXE etc. : <http://www.merlyn.demon.co.uk/programs/> - see in 00index.htm
Dates - miscdate.htm estrdate.htm js-dates.htm pas-time.htm critdate.htm etc.