The story starts from 1995, The Netscape Navigator browser was very popular and getting very high adoption from companies all over the world. Although it was paid browser, companies were happily paying for it. Then Microsoft jumps in and tried to acquire it but the deal was not happened. Then the browser war started between both the giants. Microsoft built their own version called Internet Explorer and gave it for free. Netscape share price starts declined and company starts making more and more losses every quarter.
Why would someone pay for Netscape whereas IE was there for free.
Finally, Netscape file for bankruptcy and they offer the browser for free and gave it to ECMA.
In 1996 JS brought to ECMA Standards group. ES1 came in 1997, ES2 in 1998, ES3 in 1999. Then conflicts starts in ECMA committee so it took huge time, almost a decade for introducing new standards. Finally much awaited ES5 standard came in 2009 and it blew up the entire web development scenario. we got AJAX, prototype, jQuery, dojo, and mootools ; also npm.