What's New in EdgeHTML 12
Microsoft Edge introduces EdgeHTML, a new "living" engine designed with interoperability at its core, to ensure that you are always getting the latest and greatest Windows web platform. Microsoft Edge presents a clean break from the past, free from the legacy code needed to support ActiveX controls, Browser Helper Objects (BHOs), and other bygone web development practices. Additionally, Microsoft Edge provides native PDF support. As of IE11, legacy document modes have been deprecated, and with Microsoft Edge, the browser infrastructure to support them does not exist. Check out the IEBlog for more info.
Here are the changes shipped with EdgeHTML 12 in the initial release of Windows 10 (07/2015, Build 10240). For an overview of changes to the overall Microsoft Edge browser, see A break from the past: the birth of Microsoft's new web rendering engine and A break from the past, part 2: Saying goodbye to ActiveX, VBScript, attachEvent....
Here's the permalink for the following list of changes: https://aka.ms/devguide_edgehtml_12.
Content Security Policy 1.0
Microsoft Edge now implements Content Security Policy (CSP) 1.0. The CSP security standard enables web developers to control the resources (script, CSS, plugins, images, etc.) which a particular page can fetch or execute with the aim of preventing cross-site scripting (XSS), clickjacking, and other code injection attacks seeking to execute malicious content in the context of a trusted web page. Check out Content Security Policy for more information about CSP in Microsoft Edge.
Microsoft Edge provides an easy way to add visual effects to elements. Using the
filter property you can add blurs, adjust the brightness, add a drop shadow, change the opacity, and more to an element. Using purely CSS, you can apply multiple filter effects to one element and animate the filters. For more information, see Filter effects.
Media Capture and Streams
New HTML element and attributes
sizesattributes (Microsoft Edge Developer blog post)
Object RTC API
Microsoft Edge provides a reading view for a more streamlined, book-like reading experience of webpages without the distraction of unrelated or other secondary content on the page. Reading view can be toggled on or off from the Reading view (book icon) button on the address bar (or with Ctrl + Shift + R). Visit Reading view for more information.
Search provider discovery
Rich search integration is built into the Microsoft Edge address bar, including search suggestions, results from the web, your browsing history, and favorites. Microsoft Edge follows the OpenSearch 1.1 specification to discover and use web search providers. If you are a search provider, read more about how to ensure that Microsoft Edge supports your service.
Support for WebKit APIs
For improved compatibility, Microsoft Edge supports a variety of "-webkit-" prefixed APIs. For a full list of supported "-webkit-" APIs, use the API Catalog.
audio element allows for basic streaming audio playback, Web Audio API provides a range of APIs that allow you to play multiple sounds with tight synchronization, and apply gain, fades, transitions, and basic effects on mixed audio. Read more about Web Audio in the Dev guide and on the Microsoft Edge Developer blog.
New APIs in EdgeHTML 12
Here's the full list of new APIs in EdgeHTML 12. They are listed in the format of [interface name].[api name].
Many of these APIs were available in IE11. The data below for EdgeHTML 12 is offered as a baseline for comparing the initial version of EdgeHTML to later versions.