- From: Ian Hickson <ian@hixie.ch>
- Date: Wed, 25 Aug 2010 00:35:58 +0000 (UTC)
On Fri, 30 Jul 2010, zhao Matt wrote: > > Quote from: HTML spec -4.3 Scripting > "Otherwise: > The user agent must immediately execute the script block, even if other > scripts are already executing." > > Quote from: "JavaScript - The Definitive Guide, 5th Edition" > "The core JavaScript language does not contain any threading mechanism, and > client-side JavaScript does not add any. Client-side JavaScript is (or > behaves as if it is) single-threaded." > > Q1: Can JavaScript run in parallel in HTML5 ? > Obviously, the book thinks Client-side JavaScript is (or behaves as if it > is) *single-threaded*. > However, > HTML5 spec states 'the user agent must immediately execute the script block, > even if other scripts are *already* executing.', > Does it imply that scripts can be run in parallel? No, but it is reentrant, which is what the HTML spec is referring to here. > Q2: > Quote from: HTML spec -4.3 Scripting > "Running a script: When a script element is to be run, the user agent must > act as follows:..." > The process includes 9 steps, but I don't sure which step will take the > attribute 'async' into consideration. On Fri, 30 Jul 2010, Boris Zbarsky wrote: > > Um... Step 9, which is the only one that mentions it, no? > > Having an "async" attribute prevents a script from taking the first two > options in that step. Right. -- Ian Hickson U+1047E )\._.,--....,'``. fL http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 24 August 2010 17:35:58 UTC