Internet Explorer 8 will introduce "compatibility" meta tag

The developers of Internet Explorer 8 have joined forces with the Web Standards Project (WaSP) to develop a new HTML header aimed at ensuring web pages display correctly in future browsers. Web pages would use this header to specify which browser versions they are compatible with. In the future, code such as:

<meta http-equiv="X-UA-Compatible" content="IE=8" />

would tell a browser that the page was rendered correctly by the specified software. The client may then be able to adapt its display to match the specified browser's properties. It will also be possible to specify multiple browsers (for example "IE=8;FF=3") or incorporate the header via HTTP.

According to WaSP and the IE team, the tag is aimed at solving the problem of future browser versions potentially rendering web pages in different ways from current ones, as different rendering could make web pages less usable in the future. The tag should replace the practice of Doctype switching, which allows web designers to make browsers choose a backward compatible "quirks" mode by inserting a specific doctype; the limitations of doctype switching became apparent with the introduction of Internet Explorer 7, when the rendering of numerous web sites suddenly went wrong despite the fact that they used this method.

A host of critics have already voiced their concerns; the tag has similarities with the "optimised for..." messages seen on web pages in the past, or with the attempts to offer different versions of a web site for different browsers. However, web standards experts like Peter-Paul Koch of Quirksmode.org or CSS expert Eric Meyer, who has come out in favour of X-UA-Compatible headers, point out that this was not a valid comparison. Many critics, however, think that web and browser developers may face an almost insurmountable legacy which could be avoided by focussing on future-proof web standards instead of browser peculiarities. It remains to be seen whether other browser vendors will adopt the X-UA-Compatible header.

(ehe)