[whatwg] Script loading and execution order for importScripts

Oliver Hunt oliver at apple.com
Sat Mar 7 12:54:13 PST 2009

Yes, i realise it does more than _just_ a syntax check, but the user  
observable effect is just the success or failure of syntax check :D


On Mar 7, 2009, at 12:51 PM, Boris Zbarsky wrote:

> Oliver Hunt wrote:
>> If by "compilation" you mean you're (effectively) just doing a  
>> syntax check then webkit is able to this, although it has a  
>> reasonable cost associated with it
> "Compilation" in this case is parsing and compilation to  
> SpiderMonkey bytecode.  This does include syntax checks, of course,  
> but also an optimization pass (constant folding, some simple dead  
> expression elimination, that sort of thing) and produces the actual  
> object that can be executed (which is quite distinct from the  
> character array that is input to the compilation process).
> This is not a trivial cost at the moment: it's about 10-20% of the  
> cost of loading and executing some of the large scripts out there  
> which have all sorts of function definitions but don't immediately  
> run all the code (e.g. the scripts loaded by gmail).
> -Boris

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