- From: Mikko Rantalainen <mikko.rantalainen@peda.net>
- Date: Wed, 03 Jul 2013 10:58:59 +0300
- To: whatwg@lists.whatwg.org
Boris Zbarsky, 2013-06-29 05:02 (Europe/Helsinki): > On 6/28/13 6:51 PM, Tab Atkins Jr. wrote: >> querySelector is simply a more powerful querying function than the old >> DOM methods, > > And somewhat slower as a result, note. If that's true, I would consider that as a bug. It should be really simple for an UA implementation to optimize as following querySelector("#foo") -> getElementById("foo") querySelectorAll("foo") -> getElementsByTagName("foo") as long the latter (internal) implementations were available and had better performance. Or, were you really talking about the difference between having to scan the string given as a parameter to see if it looked like "simple" selector that matches the old DOM method implementation? I understand that JS+JIT allows faster method dispatching with getElementById() than with querySelector() plus checking the characters of the first parameter. I'd *guess* that that difference is meaningless compared to walking the element tree or even doing hash lookup for the id which is required to implement even the old DOM methods. -- Mikko
Received on Wednesday, 3 July 2013 07:59:32 UTC