Later modes (IE10 Mode, IE11 Mode, and EdgeHTML Mode) are based on ECMAScript Language Specification 5.1 Edition [ECMA-262/51]. Section 2.9 of this document specifies extensions to that standard that are available in these modes. The extensions in IE9 Mode described in sections 2.1 to 2.8 are available in these modes also. However there are these exceptions:
The extensions in section 2.9.4 are not available in IE9 Mode or IE10 Mode.
The extensions in section 2.1.1 are not available in IE11 Mode or EdgeHTML Mode.
The extensions are as follows: