What is esmascript?

Ecmascript is a script standardized by the European Computer Manufacturers Association (ECMA) through ECMA-262ProgramDesign Language. This language is widely used on the World Wide Web and is often called JavaScript or JScript, but in reality the latter two are extensions of the ECMA-262 standard.
Sun and Netscape introduced Javascript in December 1995.

In March 1996, Wangjing communication company published 2.0 webscape navigators that support JavaScript.

In August 1996, Microsoft introduced Javascript into Internet javaser3.0 and named it JScript.

In November 1996, Netscape Communications submitted JavaScript to the European Computer Manufacturers Association for standardization.

The first version of ECMA-262 was adopted by the European Computer Manufacturers Association in June 1997. And named the ECMA-262 standard ecmascript.

JavaScript and JScript are compatible with ecmascript, but include functions beyond ecmascript.