Internet Explorer 8 Beta 2 and Web Standards
Internet Explorer 8 Beta 2 was released today. There are several cool UI enhancements that this beta brings to the table that I won’t cover in this post, but you can learn more about them on the IEBlog. Instead, I want to talk about how beta 2 affects IE’s relationship to web standards.
First, CSS Expressions are no longer supported in Standards Mode:
Also known as ‘Dynamic Properties’, CSS expressions are a proprietary extension to CSS with a high performance cost. As of Internet Explorer 8 Beta 2, CSS expressions are not supported in IE8 standards mode. They are still supported in IE7 Strict mode and Quirks mode for backward compatibility.
In case you don’t know, CSS expressions were actual bits of JavaScript that you could run from CSS rules; this was commonly used to simulate the CSS max-width property for IE:
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div.someClass {
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/* Internet Explorer */
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width: expression(document.body.clientWidth> 600) ? “600px” : “auto”;
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/* Standards-compliant browsers */
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max-width: 600px;
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}
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IE 8 beta 2 also now supports alternate style sheets:
Internet Explorer 8 now supports alternative style sheets as specified by HTML4 and CSS2.1. The alternative styles that are defined by the Web page author is available through the Style menu under the Page menu. The styles are also available through the Style menu under the View menu. The No Style option on either menu can be used to disable all authors styling.
In terms of the Known Issues with IE 8 Beta 2, the first is related to Ajax bookmarking and back button support and using window.location.hash to do cross-domain communication:
Internet Explorer 8 create entries in the travel log and back button for each instance of window.location.hash that is set. This is part of the behavior for Internet Explorer 8 AJAX Navigation. If you use this technique to communicate between documents, we recommend that you switch to the Internet Explorer 8 Cross Document Messaging feature that is based on Section 6.4 of the HTML 5.0 specification.
Finally, there are some issues with the onload event for IE’s XDomainRequest object that helps with cross-domain communication:
The onload event may not fire reliably. We recommend you use the onprogress events which continues to fire as the data is received.
Unfortunately this is it for this release. You can see the full Beta 2 release notes, or download it yourself.
On a related note, IE 8 Beta 2 includes cross-site scripting attack (XSS) protection:
The XSS Filter operates as an IE8 component with visibility into all requests / responses flowing through the browser. When the filter discovers likely XSS in a cross-site request, it identifies and neuters the attack if it is replayed in the server’s response. Users are not presented with questions they are unable to answer – IE simply blocks the malicious script from executing.
Finally, PPK has also published a post on IE 8 Beta 2 and its changes.
