On 2/8/11 4:13 PM, Boris Zbarsky wrote:
On 2/8/11 3:56 PM, Kyle Simpson wrote:
Yes, it's important to note that it's not even the *execution* of
JavaScript code that's actually the particular issue, but rather just
the parsing of it (even if invoking of the functionality is deferred
until later) that causes the biggest slowdown, in most cases.
Here's the thing. Parsing is a black-box behavior. Nothing says a
browser needs to do it right before execution, that it needs to happen
on the main thread, or that it's happening at all.
Maybe I should clarify. The above is the case now. If you have
normative language that requires parsing to happen or not happen at
particular times, then presumably you also expose a way to tell whether
it's happened (otherwise the requirement is vacuous). And if you do so,
then I think you overconstrain things and prevent some browser-side
optimizations that I'd like to see happen.
-Boris
