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by olliej 1355 days ago
I actually just went and tested and in webkit at least my 100% perfect test case I had querySelector taking 2x longer than getElementById. I tried understanding what the current webkit code does but the selector matching code is now excitingly complex due to the CSS JIT.

Many many years ago I recall querySelector starting out with a check for #someCSSIdentifier and shortcutting to the getElementById path, but maybe my memory is playing tricks on me.
1 comments
esprehn 1355 days ago
Yup that's what it did, and Chrome still does. After much research and prototyping the CSS JIT didn't improve real world content (especially given the complexity) so it was never added to Chrome.
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