Comparison of layout engines (HTML5)

The following tables compare support of HTML5 differences from HTML4 for a number of layout engines.

The specification is still a working draft, not a W3C recommendation, and thus not stable. Unless otherwise specified in footnotes, comparisons are based on the stable versions of the programs without any add-ons, extensions or external programs.

Elements
While many of these elements, such as, have not been implemented natively in layout engines, support may be very easy to emulate using CSS or JavaScript.

Form elements and attributes
Many of these features can be emulated with third-party libraries.

Next-generation additions
The WHATWG version of HTML5 also includes additional features that are not technically HTML5, which are called "next-generation additions still in development" by the spec.