Releasing DOMAssistant 2.6 – overall fastest CSS selectors, plugins and more

February 20th, 2008 by Robert Nyman

Today marks the beginning of a new stage for DOMAssistant. It is time for version 2.6 to see the lights of day, and it is packed with improvements, features and an infrastructure to back it up!

What’s new

Overall fastest CSS selector performance in the market

One of things we have focused very hard on with this release is performance. Performance is vital in any web site or application, but it is often overlooked, or at least underrated. Therefore, a lot of work has gone into fine-tuning the CSS selectors in DOMAssistant, to give results as fast as possible, while also making sure the selectors return accurate matches.

I’m proud to say that DOMAssistant currently has the fastest overall CSS selector performance, where it is noticeably faster than the other JavaScript libraries in all web browsers, but Internet Explorer. In Internet Explorer, it is the second fastest (marginally faster than jQuery), behind Ext JS.

Take the Slickspeed test to see for yourselves (my opinions about the Slickspeed test)!

Using querySelectorAll and native getElementsByClassName

Safari has implemented querySelectorAll in their latest nightly builds of WebKit, which means that it will be in an upcoming version of Safari. It is a native support (and in a W3C draft) for using CSS selectors to select elements, and the results are astounding! Download a nightly build of WebKit (don’t worry, it won’t mess up existing installations) and hold on to something!

Upcoming versions of Safari, Firefox and Opera will support getElementsByClassName natively, so DOMAssistant utilizes that where it’s available.


Where querySelectorAll and getElementsByClassName aren’t available, DOMAssistant resorts to XPath to select elements, which is an approach that also has very impressive performance results, not to mention native web browser support. The only web browser not supporting XPath is Internet Explorer, where the only option is “regular” looping through elements.


The idea is to keep the DOMAssistant core functionality as small, slimmed and optimized as possible, while we definitely respect and understand the needs other web developers, as well as us, have regarding extending that functionality. Now DOMAssistant offers an extremely easy-to-use plugin functionality, which hooks in on top of the DOMAssistant core.

For example, you might need a script to validate all the input fields in a document, if they have the class mandatory. Just customize your own validate function and use the plugin approach to add it to the DOMAssistant core. For example, your syntax can then look like this:

$("#contact-form input.mandatory").validate();

Read more about how to do it in How to create a plugin.

All plugins created will be publicly listed in the plugins page, sorted into categories so you can find the type of plugin you’re looking for. If you feel a certain plugin is missing, feel free to submit your own plugin.

The $$ method

In earlier versions, there has been some confusion about what to send in to the $ method. It would accept plain ids, CSS selectors and objects. However, by supporting the mix of ids and CSS selectors, it ruled out sending in just a certain tag, since it would then be interpreted as an id rather than a CSS selector.

With the new plugin structure in place as well, this change was inevitable. It had to become consistent so everyone could start adding their own functionality, and get back expected results.

Another factor was that there are times when there’s a need to work directly with properties and methods on the native DOM element (e.g. offsetHeight, style etc), whereas the $ method returns a DOMAssistant collection of elements mainly intended for DOMAssistant methods and chaining.

Therefore, we have decided to introduce the $$ method, which returns a direct DOM reference, but with all the extra DOMAssistant methods applied to it as well. So, to summarize:

The $ method

Accepts either a CSS selector or an object reference. E.g. $("#container .external-links"), $(document). Fails silently if you try to call a method when the selector didn’t return any matches; i.e., $("input[type=text]").addClass("text-fields") won’t throw an error trying to call the addClass method, even if the $ selector didn’t match any elements.

Returns: A collection of one or several nodes for CSS selectors/object reference when an object was sent in.

The $$ method

Accepts a string parameter, expected to be the id of an element. E.g. $$("container"), $$("navigation"). Will throw an error if you try to call a method, if there wasn’t any match.

Returns: A direct reference to the DOM element.

Backwards compatibility issue

The result of this is that if you have used the $ method and only passed in ids, then it will not work with this new release. It will be regarded as a CSS selector and element names. I am truly sorry for this, but it was vital for the future of DOMAssistant.

But fret not! The very simple solution for those scenarios is to just replace $ with $$, and it will work exactly as before! So, make the change now and you should be DOMAssistant future compatible.

Support for multiple simultaneous AJAX calls

Before, the get and post methods would just allow one call at the time, and if another was started before the previous had finished, the previous call got cancelled. This has now been addressed, so you can have as many simultaneous calls as you want.

Bug fixes

  • Fix for addContent method calls on a collection.
  • Fix for replaceContent method calls on a collection.
  • Fix for id bug in Internet Explorer and Opera, where it matched elements with that name as well (id and name mixups bug).
  • Removed unnecessary attribute removal in the replaceWithAJAXContent method for the AJAX module.
  • (Re)Added support for XUL events (DOMMouseScroll etc) with the addEvent method (this fell out in between versions).


Talking about infrastructure, I mean what has happened around the DOMAssistant JavaScript library.

Discussion forum

Something that has been asked for numerous times is a public forum where peole can ask questions about or discuss DOMAssistant. Now there is a DOMAssistant discussion forum where anyone can get help, or discuss how to implement a certain thing

The DOMAssistant Team

A DOMAssistant team has been formed, and its tasks consist of testing DOMAssistant, helping out in the discussion forum, evangelizing, analyzing and helping out with the code itself and general advisory functions. They are invaluable to DOMAssistant, and the team members are:

Offline documentation

Something which has been requested is the ability to download the DOMAssistant documentation to read it through or print it, without having to use the DOMAssistant web site itself. Now there’s a PDF download in the documentation section to cater to those needs.

Web site and blog

Previously, DOMAssistant was hosted at, but it had to stand on its own. It also features this blog to talk about DOMAssistant or general JavaScript topics, and to make announcements about releases.

What about animations?

I’ve gotten a lot of feedback from people saying that they love DOMAssistant, but now and then they have a need to use animations in a web page. My philosophy is to have as little as possible in the DOMAssistant core code, I’d rather take things out than add more methods, and I don’t regard animation functionality as being important enough to be in there.

However, of course there’s a need for animations, and just as we speak, Pelle of the DOMAssistant team is working hard on putting together a plugin to DOMAssistant with just that. Stay tuned, we’ll alert you in the blog as soon as it’s available.

Till then, feel free to extend DOMAssistant with your own plugin! :-)

Try DOMAssistant out!

Now download DOMAssistant and try it out. Write your own plugins and enhance your existing web sites!

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14 Responses to “Releasing DOMAssistant 2.6 – overall fastest CSS selectors, plugins and more”

  1. [...] There are a number of improvements and new goodies in the new 2.6 version, so please check out the release blog post in the DOMAssistant blog. [...]

  2. [...] The JavaScript-library of my choice and which I’m part of the team behind, DOMAssistant, has been released in a new version. [...]

  3. Hi, I really enjoy your work Robert. I did not had the chance to use your library, but I feel inspired about the hard work you put into this. So tomorrow I will take the time to play around with it and hopefully start programming some plug-ins :)

    I was searching for a good libary lately, but all seem to be bloated to begin with. And finding a good way to just include the necessary modules in Ext, YUI and co. are just to time consuming!

    I believe that your libraray has a good chance to become a very popular libraray for people like me who don’t want to rely on stuff from others and prefer to do it by themselves. Your library gives me the opportunity to start working on my own extensions as I see fit. Thanks :)

    Hope I can contribute something useful!!!

  4. Robert Nyman says:


    Thank you for those kind words!
    Please try out the plugins structure and let me know how it works out for you!

  5. Rey Bango says:

    Congrats on the new release Robert! :)

  6. [...] 2.6 Released DOMAssistant 2.6 has been released and the team focused on performance for this [...]

  7. Robert Nyman says:


    Thank you! :-)

  8. [...] DOMAssistant 2.6 has been released and the team focused on performance for this version. [...]

  9. [...] der Bereitstellung der Version 2.6. des DOMAssistant hat das Entwicklerteam um den Schweden Robert Nyman ein wahres Kunststück in Sachen [...]

  10. [...] DOMAssistant 2.6 has been released and the team focused on performance for this version. [...]

  11. [...] There are a number of improvements and new goodies in the new 2.6 version, so please check out the release blog post in the DOMAssistant blog. [...]

  12. [...] Releasing DOMAssistant 2.6 – overall fastest CSS selectors, plugins and more [...]

  13. kuse says:

    omg, why doomassistant method addcontent fail to insert a row in table element when I use Internet Explorer ;< Does anybody know how to fix it?

  14. [...] For Robert’s own, more detailed, description of the news and changes in DOMAssistant 2.6, read his post on the DOMAssistant development blog: Releasing DOMAssistant 2.6 – overall fastest CSS selectors, plugins and more. [...]