- “Quirks mode” remains the same, and compatible with current content.
- “Standards mode” remains the same as IE7, and compatible with current content.
- If you (the page developer) really want the best standards support IE8 can give, you can get it by inserting a simple <meta> element. Aaron gives more details on this in his article.
We believe this approach has the best blend of allowing web developers to easily write code to interoperable web standards while not causing compatibility problems with current content. We also think this approach allows developers to opt in to standards behavior on their own schedule and as it makes sense to them, instead of forcing developers into a responsive mode when a new version of IE has different behavior on their current pages.
Also check this articles: A List Apart which says :
...For many years, we designers and developers have been yearning for a way to reliably deploy our websites. In addition to the headaches of writing cross-platform styles and scripts, we’ve had to deal with the fallout from new browser releases that inevitably broke something we couldn’t possibly have anticipated. It’s never fun explaining the cause of an unexpected break to our clients, bosses, and users. But with IE8’s introduction of version targeting, there is a light at the end of the tunnel. I, for one, hope other browser vendors join Microsoft in implementing this functionality.