Hell must have frozen over or something. I don’t know if this just fixes certain kinds of leaks or all of them; explicit circular references in your code should still be avoided. Xopus, via Snook:

At Xopus we develop a pretty big (~50k lines) JavaScript application to edit XML documents through a WYSIWYG interface. With such a large application there’s a large risk of memory leaks. Indeed, this is what we’ve been experiencing in Internet Explorer 6. We’ve also seen a decrease in performance as memory usage increased. These leaks, however, do not occur in Internet Explorer 7. And, as of just 10 days ago, they no longer occur in IE6 on Windows XP.

On June 12th, Microsoft released security update MS07-033. Included in this update is the following:

General distribution release (GDR) fixes
A memory leak occurs in Internet Explorer 6 when you view a Web page that uses JScript scripting on a Windows XP-based computer (KB929874)

And indeed, IE 6 on Windows XP no longer leaks memory, nor performance. This is great news for all JavaScript hackers, there’s no need to worry about memory leaks anymore!

The one cave-at is that this fix is only available for Windows XP. For Xopus this means we’ll still have to fix the leaks, since some of our clients are still running Windows 2000. Users who haven’t installed the latest security updates will also experience memory leaks in IE 6. In the end though, Microsoft fixed the memory leak issues in Internet Explorer, and I’m thankful for that.

So I spent an entire day discovering a quirk about javascript that I must now share. In a previous post on creating default settings for classes/objects I discussed the following technique:

var Widget = new Class({
	initialize: function(element, options){
		this.element = element;
		this.options = Object.extend({
			offsetX: 0,
			offsetY: 0
		}, options || {});
		this.setPosition();
	},
	setPosition: function(){
		this.element.setStyles({
			left: this.options.offsetX + 'px',
			top: this.options.offsetY + 'px'
		});
	}
});

Now, this isn’t a very useful class, but it illustrates the technique. The functions in our class don’t have to worry if the options are defined; they are either what the default value is or they are what the user passed in. If the user elects to just pass in a subset of the values, that’s fine:

var myWidget = new Widget(myElement, {offsetX: 100});
//myElement will be offset by 100 on the left,
//zero (the default) on the top

But what if you want to extend the functionality of your class later? What if you want to be able to insert more default options?

Here’s what I was doing that caused me trouble: Read the rest of this entry »

Brandon S. writes: The first release candidate of IE version 7 came out today…
And then on ajaxian:
The IE Team has posted more details on the IE7 CSS changes so we can all get prepared:

We are currently locking down IE7 for shipping and I wanted to give an update on the CSS work that went into IE7. Chris originally outlined our plans for IE7, and we listened to a lot of feedback (blog, connect database, conferences, our WASP partnership etc.) to help us address the most grievous bugs and prioritize which features to put in for IE7. I like to thank especially the contributors on this blog for their participation. Your feedback made a difference in deciding what issues to address.

We understand that we are far from being done and we know we have still a lot of work ahead of us. IE 7 is a stepping stone in our effort to improve our standards compliance (especially around CSS). As an example, in the platform we did not focus on any proprietary properties – though we may try out new features in the future using the official ms- prefix, following the CSS extension mechanism. We also work very closely with the W3C CSS working group (which I am a member of) to help clarify assumptions in our implementation and drive clarifications into the spec. I really like to thank everyone who helped us here.

In all, we made over 200 behavior changes (bug fixes or new features) under strict mode to improve CSS2.1 compliance. All this work (with the exception of transparent PNGs) has been done under the switch only, since all changes required behavioral updates to be more in line what the CSS spec specifies. To preserve application compatibility we will not make any behavioral changes to ‘quirks mode’ as it has been established since IE6.

Read about the many changes that have been made.

Continuing in my efforts to make my code stop leaking (fun!), I’ve been working on a popup handler I wrote recently (which I plan to post and share as soon as, you know, it doesn’t leak). Read the rest of this entry »

It’s been a while since I last posted. Partly because I haven’t seen anything super interesting and partly because I’ve been heads-down on something super-duper secret. I’ll post on it when I’m good and ready.

The super secret thing I’m working on has a problem: it leaks. It leaks in Firefox, which I’m told is a rare thing. I feel special. I emailed my pal Alex about it; he’s an old friend who happens to have unstoppable code kung-fu and he always seems to have something to share that’s worth listening to. He writes back regarding my javascript memory leak with this pearl of wisdom that probably would have taken me a long time to figure out: Read the rest of this entry »