Netscape Navigator was the most widely used web browser at that time and Microsoft had licensed Mosaic to create Internet Explorer 1.0.
The introduction of new features often took priority over bug fixes, resulting in unstable browsers, fickle web standards compliance, frequent crashes and many security holes.
The World Wide Web Consortium (W3C), founded in 1994 to promote open standards for the World Wide Web, pulled Netscape and Microsoft together with other companies to develop a standard for browser scripting languages called ECMAScript.
Subsequent releases of JavaScript and JScript would implement the ECMAScript standard for greater cross-browser compatibility.
[1] In the early part of the century, practices such as browser sniffing were deemed unusable for cross-browser scripting.