Compatibility

New and updated features in Microsoft Edge for Windows 10 are focused around the themes of browser interoperability and site compatibility. In addition to thousands of bug fixes, Microsoft Edge brings updated support for popular web standards and coding practices.

These changes include:

  • Content Security Policy 1.0
  • Document Modes
  • Drag and drop: new and legacy model support
  • EdgeHTML engine
  • Fullscreen API changes
  • Platform for Privacy Preferences 1.0 (P3P 1.0) removal
  • SPDY support removal
  • Synthetic event support
  • User Agent string changes
  • Web Cryptography API updates

See the Changes introduced in Microsoft Edge for Windows 10 topic in the Compatibility Cookbook for further details.

Content Security Policy 1.0

Microsoft Edge implements Content Security Policy 1.0 (CSP). If you implement CSP at the server level, it will disable or break inline JavaScript code and onclick handlers. While those are not current best practice, they do appear more often in older webpages. See the Compatibility Cookbook for more.

For best performance, load all JavaScript from external files and use addEventListener for handling clicks.

Document Modes

Document modes were deprecated with Internet Explorer 11. In Microsoft Edge, developer-initiated switching of the document mode via the x-ua-compatible header will be ignored on most Internet sites and they will be rendered with the EdgeHTML engine. Read more about document mode deprecation in the Compatibility Cookbook.

Windows 10 provides enterprise customers tools for managing Microsoft Edge in coordination with Internet Explorer and Enterprise Mode fallback for compability. For more info, see Windows 10 browsing on TechNet.

Drag and drop: new and legacy model support

With Microsoft Edge, you can now retrieve, add and remove data from the underlying drag and drop data store through the DataTransferItemList provided by the DataTransfer.items property.

The legacy drag and drop model is still supported and has been updated for Microsoft Edge, with full MIME type support for string data with the getData and setData methods.

See the Compatibility Cookbook for further details.

EdgeHTML engine

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.

Fullscreen API changes

Microsoft Edge moves from experimental to official support of the Fullscreen API and removes the "ms" prefixes on the associated methods, properties, events, attribute, and CSS selectors. Additionally, for improved compatibility with legacy code around the World Wide Web, the API's webkit-prefixed variants are also supported. The Compatibility Cookbook has more information on the specific changes.

Platform for Privacy Preferences 1.0 (P3P 1.0) removal

Support for P3P 1.0 has been removed in Windows 10 for both Microsoft Edge and Internet Explorer 11 for Windows 10. The Compatibility Cookbook has more info.

SPDY support removal

Support for SPDY/3 has been removed in favor of HTTP/2. This should have minimal developer impact. The Compatibility Cookbook has more info.

Synthetic event support

Using the createEvent()/initEvent() pattern to create synthetic DOM events is deprecated.

Microsoft Edge has implemented the more standards-compatible new Event() pattern. See Synthetic events for details.

User Agent string changes

The User Agent string has changed. The User Agent reported for Microsoft Edge is:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.<OS build number>

The User Agent reported for Microsoft Edge for Windows 10 Mobile is:

Mozilla/5.0 (Windows Phone 10.0; Android 4.2.1; DEVICE INFO) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Mobile Safari/537.36 Edge/12.<OS build number>

We are also removing a number of outdated feature tokens and adding the new Edge token. For a more detailed list of changes, please see our extended guidance on user agent string changes.

Web Cryptography API updates

The W3C Web Cryptography API specification has changed from an event-driven model to a new model based on JavaScript Promises. Microsoft Edge introduces support for this new model and removes support for the legacy model.

See the Compatibility Cookbook for further details.