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- .closest(Array) in jQuery 1.4December 18 2009
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A new method signature is slated for jQuery 1.4: .closest(Array). It builds upon the previous .closest() method and hyper-optimizes the logic needed for handling event delegation (and live events).
closest() (and by extension, is()) has become a critical function in jQuery. With more people using live events reducing any overhead has become of the utmost importance. Every time an event fires that live is bound to (such as click or mousemove) jQuery uses the closest() method to go from the target element and find the nearest element that matches the specific selector. The more handlers that are bound, though, the more computationally expensive it becomes.
In jQuery 1.4 we've added closest(Array) which gives us the ability to batch these selector checks together and reduce the amount of time that we spend traversing the DOM.
Example
- .nodeName Case SensitivityNovember 24 2009
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When working with the DOM .nodeName property there are two hard-and-fast rules that most people abide by:
- The node names of HTML elements are always uppercase, even if they're explicitly created using lowercase characters. <html> will result in a .nodeName === "HTML" (see the HTML 5 draft).
- The node names of XML elements are always in the original case, as specified when they're created. <data> will result in a .nodeName === "data", <DATA> will result in a .nodeName === "DATA".
Knowing these rules can be useful because it allows you to optimize your code. If you know that you're in an HTML document you can avoid having to upper/lowercase your .nodeName checks and you can just always assume that you're dealing with a .nodeName that's uppercase. This results in faster selectors for Internet Explorer and other minor optimizations.
However recently I've been running across two cases that've been especially problematic and have bucked the trend.
Importing Nodes from XML
The first is for browsers that support the adoptNode/importNode DOM methods. These methods allow you to move (or clone) a node from one DOM document to another. In this way you can move an XML node from an XML document and insert it into an HTML document. Normally this shouldn't matter much but, as it turns ou
- Deep Tracing of Internet ExplorerNovember 17 2009
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After reading a recent post by Steve Souders concerning a free tool called dynaTrace Ajax, I was intrigued. It claimed to provide full tracing analysis of Internet Explorer 6-8 (including JavaScript, rendering, and network traffic). Giving it a try I was very impressed. I tested against a few web sites but got the most interesting results running against the JavaScript-heavy Gmail in Internet Explorer 8.
I typically don't write about most performance analysis tools because, frankly, most of them are quite bland and don't provide very interesting information or analysis. dynaTrace provides some information that I've never seen before - in any tool on any browser.
dynaTrace Ajax works by sticking low-level instrumentation into Internet Explorer when it launches, capturing any activity that occurs - and I mean virtually any activity that you can imagine. I noticed very little slow down when running the browser in tracing mode (although it's sometimes hard to tell, considering the browser). However all of the tracing is recorded and saved for later, making it easy to record sessions for later analysis.
- Google Groups is DeadOctober 27 2009
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As far as I'm concerned, Google Groups is dead.
For the jQuery project we've run all of our community discussions through Google Group mailing lists for the past three years. At this moment the main jQuery group is the second most popular programming group (next to Android developers) clocking in at over 21,000 members. We also have the jQuery Dev and jQuery UI groups. The main jQuery group averages around 83-143 messages per day. I also use Google Groups for discussion on a number of my other projects (Processing.js, Env.js, Sizzle.js, and TestSwarm).
This post isn't so much about the usefulness of mailing lists as a discussion medium, it's the complete failure of Google Groups as an adequate purveyor of public discussion software. For the jQuery project we're already in the process of moving the full discussion area to a forum that we control. We should have it set up, and everything moved over, withi
- Talks at the 2009 jQuery ConferenceSeptember 16 2009
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This past weekend was the 2009 jQuery Conference here in Boston. It was an incredible event - 300 people attended and a ton of discussion, collaboration, and learning happened.
Nearly the entire jQuery project team had the opportunity to meet for two days prior to the conference and hash a number of things out - figuring out most of the planning for the upcoming year. The core dev team also had the opportunity to meet and work for two days just after the conference. We're much closer to shipping 1.3.3 now (which is likely to become 1.4, with all the new features that're being added).
(Left to Right: Mike Hostetler (Infrastructure), John Resig (Core), Paul Bakaus (UI), Brandon Aaron (Core), Richard D. Worth (UI), and Scott Jehl (UI and Design team)A full list of the presentations that were given can be found on the events site. All the presentations that I gave can be found below.
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