Brandon Eich was hired to integrate the Scheme programming langauge into the Netscape browser. But when Netscape cut a deal with Sun Microsystems to bring Java Applets to their browser, his mission was altered to create a more Java-like langauge. He developed a prototype in only ten days, that blended Java syntax, the Self object-orientation approach, and Scheme functionality.
The ECMA standard is maintained by ECMA International , not the W3C. However, its development process is very similar, involving stakeholders developing proposals for new and improved features.