New and Improved features
* Opera auto update (New)
* Opera crashlogging tool (New)
* Opera Dragonfly (Improved)
* Opera inline spelling checker (New)
* Opera Mail
- Rich Text Message Composition â€” HTML authoring (New)
- Delete After X Days â€” POP-only (New)
* Opera Presto 2.2 rendering engine (Improved)
* Opera regular expression engine (Improved)
* Opera Turbo (New)
* Opera User Interface
- Opera skin elements (New)
- Opera Speed Dial configuration options (New)
- Opera Tab Bar thumbnails (New)
- Opera "pretty-printing" of unstyled XML (New)
Web specifications support
* Opera 10 Beta scores 100/100, pixel perfect on the Acid3 compliance test; see our Opera reference.
CSS (Cascading Style Sheets)
* Support for the CSS3 color:transparent value has been improved.
* Full RGBA and HSLA opacity support is now included for an easier way to make Web page features transparent. This is accomplished by the addition of a fourth argument to HSL and RGB, namely alpha transparency and results in RGBA and HSLA values. See this Opera reference.
* Support has been added for the CSS Selectors API. This feature makes the selection of DOM elements a lot simpler. It includes partial support for namespace resolver features which allow you to work with mixed namespace documents and select elements based on their namespace; see this Opera reference.
* CSS files must now be served with the correct MIME type ("text/css") in Strict mode, or they will be ignored.
HTML 5 support
* HTML 5 algorithms have been implemented for detecting charsets in HTML.
* HTML 5 end-tag and start-tag parsing, whitespace parsing, and DOCTYPE parsing have been added.
* HTML 5