The original ECMAScript 4 work led by Waldemar Horwat (then at Netscape, now at Google) started in 2000 and at first, Microsoft seemed to participate and even implemented some of the proposals in their JScript . Over time it was clear though that Microsoft had no intention of cooperating or implementing proper Java Script in Internet Explorer, even though they had no competing proposal and they had a partial (and diverged at this point) implementation on the . So by 2003, the original ECMAScript 4 work was mothballed.
The next major event was in 2005, with two major happenings in Java Script's history.
JScript, a reverse-engineered implementation of Netscape's Java Script, was part of Internet Explorer 3.
JScript was also available for server-side scripting in Internet Information Server.
The standards process continued in cycles, with the release of ECMAScript 2 in June 1998, which brings some modifications to conform to the ISO/IEC 16262 international standard.
To defend the idea of Java Script against competing proposals, the company needed a prototype. Although it was developed under the name Mocha, the language was officially called Live Script when it first shipped in beta releases of Netscape Navigator 2.0 in September 1995, but it was renamed Java Script as a marketing ploy by Netscape to give Java Script the cachet of what was then the hot new Web programming language.
Internet Explorer 3 also included Microsoft's first support for CSS and various extensions to HTML, but in each case the implementation was noticeably different to that found in Netscape Navigator at the time.
These differences made it difficult for designers and programmers to make a single website work well in both browsers, leading to the use of "best viewed in Netscape" and "best viewed in Internet Explorer" logos that characterized these early years of the browser wars.
Netscape Communications realized that the Web needed to become more dynamic.
Marc Andreessen, the founder of the company believed that HTML needed a "glue language" that was easy to use by Web designers and part-time programmers to assemble components such as images and plugins, where the code could be written directly in the Web page markup.