Comments on: ECMA-262-3 in detail. Chapter 1. Execution Contexts.

By: kevin wang

kevin wang — Mon, 07 May 2012 08:35:27 +0000

If there is only one eval context being pushed, then I guess you miss putting the globalContext at the bottom, does it look like

ECStack.push({
  context: evalContext,
  caller: globalContext
},
globalContext
);

And one more question, as you said, each script file has its own global context and all script files share another global context which is different from the script one, is it a purely implementation choice?

By: James Li

James Li — Fri, 13 Apr 2012 02:23:19 +0000

now it’s clear, thank u.

By: Dmitry Soshnikov

Dmitry Soshnikov — Thu, 12 Apr 2012 17:21:52 +0000

@James Li It seems just not the best notation I chose for eval context pushing (there is a confusion with the real push method of arrays which accepts several parameters). There only one context is pushed -- the eval's context, and the calling context is just a property: [js]ECStack.push({ context: evalContext, caller: globalContext });[/js]

By: James Li

James Li — Thu, 12 Apr 2012 00:16:27 +0000

thanks for the great article. here’s a question: since eval code using a calling context, why the stack push addtional eval context above, while pop only the calling one? what’s the difference?

By: Dmitry Soshnikov

Dmitry Soshnikov — Mon, 02 Apr 2012 05:17:20 +0000

@Paul, thanks, glad it's useful. @Michael, global context corresponds to evaluation of the script. Every script tag enters its own global execution context and is treated as separate program. However, all of these scripts are share the same global object.

By: Michael

Michael — Sun, 01 Apr 2012 08:46:14 +0000

When is created globalContext in the browser? It is diffrent for EC3 and EC5? Scripts in the browser can load and execute at different times and earlier changes in the global object can be seen later.

By: Paul

Paul — Fri, 18 Nov 2011 03:55:19 +0000

Thank you for the translation. I can’t read Russian and it was nice you take the time in giving this to us in English.

Very helpful.

By: Dmitry A. Soshnikov

Dmitry A. Soshnikov — Fri, 30 Sep 2011 14:36:38 +0000

@Hans Höglund, @Alex Bars, thanks! @David Lee, thanks,

I want to translate to Korean

Yes, great. Please contact me when the translation will be ready, I'll give a link from this article.

I would like to clarify “up to version 1.7″. Did you mean after that version it doesn’t support the feature?

Yes, because it was sort of a hack, it was banned. But you still make test in in older Firefox (2) and Rhino versions.

And also did the version mean JavaScript Version? As far as I know there is 1.8.x version of JavaScript.

Yes, exactly. The version of Mozilla's SpiderMonkey is meant.

By: David Lee

David Lee — Fri, 30 Sep 2011 14:25:30 +0000

It is a great article. I want to translate to Korean so that other my friends can take it quickly.
I have a question regarding below:

“In SpiderMonkey implementation (built into Firefox, Thunderbird), up to version 1.7, it is possible to pass a calling context as a second argument for eval function.”

I would like to clarify “up to version 1.7″. Did you mean after that version it doesn’t support the feature?

And also did the version mean JavaScript Version? As far as I know there is 1.8.x version of JavaScript.

Thanks.

By: Alex Bars

Alex Bars — Wed, 01 Dec 2010 18:24:16 +0000

Thanks, I am trying hard to understand EC, now I know why them call it “Abstract” lol!!