What’s relationship between JavaScript and ECMAScript

JavaScript was originally by Netscape, as Vulpes said. Standard ECMA-262 ECMAScript Language Specification standardizes JavaScript. It is typical for there to be some non-standrd features of JavaScript unless it is called ECMAScript.

ECMAScript is a scripting language that has been standardized by Ecma International

JavaScript is an implementation of ECMAScript which includes some extra features which are not in the standardized version. It was originally developed by Netscape.