Microsoft announced that a sizeable number of legacy IE technologies and features would not make it to Microsoft Edge – the recently announced modern web browser from the company. In one of their blogs, Microsoft detailed all the legacy technologies, browser engine components and features which are not going to be part of current Microsoft Edge.
Edge drops ActiveX, VBScript, attachEvent support
Microsoft Edge not supporting these legacy features results in many benefits to the browser- better interoperability with other modern browsers like Chrome, improved performance, security and reliability and reduced code complexity as well. Over 220,000 lines of code in MSHTML have been cleaned up from Microsoft EdgeHTML.
Few technologies and APIs which are not supported on Microsoft Edge browser:
- ActiveX – The need for ActiveX controls are diminished in HTML5 Era
- Browser Helper Objects(BHO) – would be replaced by HTML/Javascript-based extension
- Document modes – would be replaced by a single “living” document mode, compatibility tests are done with the help of about:flags switches
- Vector Markup language(VML) – 2D vector graphics are now supported via Scalable Vector Graphics (SVG) instead of VML
- VBScript – The defacto web standard Javascript ECMAScript 6 would replace VBScript
- attachEvent/removeEvent – replaced by DOM Level 3’s addEventListener/removeEventListener
- currentStyle – replaced by getComputedStyle property of DOM L2 standard
- Conditional comments – feature detection and other progressive enhancement features to replace browser-specific conditional comments
- IE8 layout quirks
- DirectX filters and transitions – similar effects can be achieved using standards-based features in CSS3 and SVG.
Other than ActiveX and BHOs, there are other legacy extensibility points that are not in Microsoft Edge which would be replaced by modern extensibility model which includes:
- Binary behaviors
- Pluggable protocols
- Shell Helper API
- Active Documents
- Custom Download Managers
- Custom Security Managers
- MIME filters
- Custom Print and Print Preview Handlers
- Explorer Bars
- Edit Designers
- Timers
- Accelerators
- Webslices
Along with this, there are various other non-interoperable APIs which have been removed. The removed APIs does not necessarily mean removed capabilities in the browser, removing these APIs results in substantial improvement to user experience in Microsoft Edge. The full details on changes in Microsoft Edge can be found in the Windows Blog.
