I'm curious as to why you only chose to optimize the selectors in .live(). Why not optimize .is()? or jQuery.filter? Optimizing jQuery.filter would yield faster results for .filter(), .is(), and .live().
--John On Mon, Aug 17, 2009 at 1:38 PM, lrbabe <lrb...@gmail.com> wrote: > > I've made some minor updates to the code to reduce the code size: > - it now uses the internal jQuery.nodeName function to check for > simple selectors involving a node name (which is also safer) > - it checks for simple selectors before checking for position > selectors > The size difference for the minified version between the current > implementation and this new one should be around 250B > The code is at the same address: http://gist.github.com/168158 > > I'm also willing to write on learningjquery.com about the new features > for event delegation introduced in jQuery 1.3: live and closest > Who should I contact for that purpose? > > Regards, > Louis-Rémi Babé > > On Aug 15, 2:23 am, lrbabe <lrb...@gmail.com> wrote: > > Thank for your quick answer John, > > > > All right, I take the code of the example, remove the part that > > updates the counter and wraps the rest with a console.profile() > > > > 1. With the orginal .closest() implementation: > > - entering the ul: function calls = 76, time = 1.5 to 2.5 ms > > - moving from a li to a li.blue: calls = 144, time ~= 3.2ms > > - moving from a li.blue to a li: calls = 103, time ~= 2.2ms > > - moving from a li to a green span: calls = 124, time ~= 2.2ms > > - moving from a green span to a red span: calls = 145, time ~= 3.2ms > > 2. With the modified .closest() implementation: > > - entering the ul: function calls = 13, time ~= 0.25ms > > - moving from a li to a li.blue: calls = 27, time ~= 0.55ms > > - moving from a li.blue to a li: calls = 13, time ~= 0.25ms > > - moving from a li to a green span: calls = 13, time ~= 0.3ms > > - moving from a green span to a red span: calls = 13, time ~= 0.3ms > > > > ...and we have only three levels of elements here. > > > > On Aug 15, 1:51 am, John Resig <jere...@gmail.com> wrote: > > > > > An interesting proposition - although before making a change of this > > > magnitude it would be good to get some performance numbers outlined so > that > > > we know how worthwhile it is. > > > > > --John > > > > > On Fri, Aug 14, 2009 at 8:33 PM, lrbabe <lrb...@gmail.com> wrote: > > > > > > Hi, > > > > > > The principle of .closest( selector ) is that it cycles through the > > > > ancestors of an event target until it finds an element corresponding > > > > to the event target, or hits the root. > > > > To check for an element matching the selectors it uses the .is > > > > ( selector ) function which collects all elements corresponding to > the > > > > selector and cycles through them to find if "this" is any of those > > > > elements. > > > > > > If my memories about my algorithm lectures are correct, the > complexity > > > > of this algorithm is O(n²). Only in the case of a selector of the > form > > > > "#id" we have an O(n) complexity. > > > > However, there is another range of selectors that could be checked > > > > with an O(n) algorithm: selectors such as "div", ".class" and > > > > "div.class". In those cases, .is( selector ) is not needed because we > > > > can directly check the ancestor's nodeType and className. > > > > > > Reducing the complexity of the .closest() function is particularly > > > > important when using event delegation with the mouseover and mouseout > > > > events: those events fire really often as the user moves his/her > > > > mouse, and the function needs to be used twice: one to check the the > > > > target is in the selector, and one to check that the related target > is > > > > in a different ancestor. > > > > > > I propose a new implementation of .closest() that is able to detect > > > > those selectors and use them to "fast-check" ancestors. The last > > > > parsed selector is cached to further improve the performances (I'm > > > > just not sure where to cache the parsed selector). > > > > > > The code is available as a gist:http://gist.github.com/168158 > > > > and can be tested here:http://www.lrbabe.com/sdoms/closest/ > > > > > > Together with the recent addition of the "context" parameter > > > > in .closest(), it makes one of the most efficient event delegation > > > > helper out there. > > > > > > Feedback would be much appreciated, > > > > > > Regards, > > > > lrbabe > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jQuery Development" group. To post to this group, send email to jquery-dev@googlegroups.com To unsubscribe from this group, send email to jquery-dev+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/jquery-dev?hl=en -~----------~----~----~----~------~----~------~--~---
