Facilitating the spread of knowledge and innovation in professional software development



Choose your language

InfoQ Homepage News New HTML Parsing Rules in IE 10

New HTML Parsing Rules in IE 10


One of the major changes in HTML 5 was the standardization for non-standard HTML, or more specifically, mal-formed HTML. Browsers are notoriously lenient when it comes to accepting HTML that contains flaws such as missing end tags. This leniency is widely credited for the continued success of HTML in the face of rival standard such as XHTML.

The HTML Living Standard reads,

This specification defines the parsing rules for HTML documents, whether they are syntactically correct or not. Certain points in the parsing algorithm are said to be parse errors. The error handling for parse errors is well-defined: user agents must either act as described below when encountering such problems, or must abort processing at the first error that they encounter for which they do not wish to apply the rules described below.

According to Tony Ross of Microsoft, Internet Explorer will start abiding by these new parsing rules in the recently released version 10, platform preview 2. While it is always best to use valid HTML, sites that cannot be fixed before IE 10 is released will need to run in legacy mode.

Another change is the removal of the following features:

Again, this only applies when not running in a legacy mode.

We need your feedback

How might we improve InfoQ for you

Thank you for being an InfoQ reader.

Each year, we seek feedback from our readers to help us improve InfoQ. Would you mind spending 2 minutes to share your feedback in our short survey? Your feedback will directly help us continually evolve how we support you.

Take the Survey

Rate this Article


Hello stranger!

You need to Register an InfoQ account or or login to post comments. But there's so much more behind being registered.

Get the most out of the InfoQ experience.

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Community comments

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p


Is your profile up-to-date? Please take a moment to review and update.

Note: If updating/changing your email, a validation request will be sent

Company name:
Company role:
Company size:
You will be sent an email to validate the new email address. This pop-up will close itself in a few moments.