By this time next year, if IE 6’s usage pattern continues to match that of IE5, IE6 will be around 13% – iedeathmarch.org

In my opinion a 13% market share is still too high to drop IE6 support completely for anything intended for consumption by the general public. Let’s not forget that the majority of computer users do not know or care what a “browser” is. They just “click on the e” or “go onto the AOL internet”.

For closed system like admin interfaces or internal web apps I see no reason why system requirements which exclude ancient browsers cannot be enforced. That’s the distinction between a website and a web app. A web app is software, and software comes with system requirements. Obviously the decision to drop IE6 support depends heavily on your target audience. So the general rule of thumb should surely be if your site/app would not suffer from IE6 compatibility don’t bust your nuts making it IE6 compatible.

My preferred method is simple. If I’ve decided that an application I’m developing is not going to be ie6 compatible i will add in some simple browser detection either server-side or with a bit a JavaScript which disables the application and shows a friendly message informing the user that they are using a very old browser. I generally give them some upgrade options in the from of links to the Firefox and IE7 download pages.

If your site or application actually works okay in IE6 but has some quirks that you’re unable/unwilling to iron out another good approach, and one taken by Facebook is to display a friendly unobtrusive message to IE6 users again explaining that they’re using very old software and some parts of the site might look/behave oddly. It would be interesting to see figures on how many upgrades have occurred as a direct result of IE6 users of Facebook. I imagine it’s considerable.

All in the the trends look promising, but no sooner will we forget about IE6 like we did IE5 then we’ll start begging for IE7 and all it’s idiosyncrasies to bow out in the same way.

IE7, don’t you just love it? What they gave us with one had in terms of CSS actually sort of working they took away with some of the stupidest niggly little bugs ever. Here’s another potentially large one i’m stumbled right into recently.

If your user agent string is more than 260 characters in length then your user agent string suddenly and almost magically becomes “Mozilla/4.0 (compatible; MSIE 6.0)”

Not what you’d expect to happen. Now, I know what your thinking. Why on god’s earth would your user agent string BE that long. The answer is simple. Toolbars and Spyware.

Toolbars and Spyware

The cool thing about Windows is that toolbars, spyware and crapware in general can and do add pointless shit to your Internet Explorer user agent string via the registry. Sounds good doesn’t it. Now consider the following:

1. Most store bough Windows PCs come pre-installed with tons of stupid toolbars and crapware
2. IE 7 isn’t much more secure than IE6 was in terms of spyware
3. Home users do not know or care about viruses and spyware

With me?

Try it yourself

You can easily trigger this bug yourself by editing the registry. Fire up regedit and navigate to HKLM/Software/Microsoft/Windows/CurrentVersion/Internet Settings/5./0User Agent/Post Platform. Create a new string key and fill up full of crap (enough to pass the 260 character threshold)

Next, close all instances of IE. Fire UP IE again and type the following into the address bar:

javascript:alert(navigator.userAgent)

Hit enter and IE7 should now tell you that it’s IE6. Awesome!

I firmly believe that this is one of the reasons behind problems such as the thickbox positioning bug that many people experience with IE7.

The workaround?

This is of course just another argument against relying on the user agent string to determine browser version. It really shouldn’t be done this way, yet it’s the method built into many JavaScript libraries including jQuery with it’s unreliable $.browser.version property.

If you really need to know if a browser is IE6 or IE7 then use something more solid like object detection. Simply testing for something like the following would be a better option than extracting unreliable data from the user agent string

A possible patch below redefines the browser version as “7.0″ only if the browser has already been identified as IE6 and the the presence of the XMLHttpRequest object suggests otherwise.

if(jQuery.browser.msie && parseInt(jQuery.browser.version) == 6 && this.XMLHttpRequest) {
	jQuery.browser.version = "7.0"
}

I’m thinking though that maybe this might not be bulletproof. If IE8 presents the same or similar “Hi i’m IE6!” behaviour then the above patch could incorrectly identify IE8 as IE7. This might not be as serious as IE7 vs. IE6 but it’s still an issue.

I just wish that Microsoft would put a bit more effort into writing good software. It’s not like they don’t have the resources.