In the early days of the web, Mosaic was a popular browser that led to the founding of Netscape. Netscape Navigator, a more advanced browser, was released in 1994 and gained widespread usage. To overcome the limitation of static web pages, Netscape sought to add a scripting language. They considered Java and Scheme but ultimately decided on a new language with Java-like syntax.
In the early 2000s, Internet Explorer dominated the browser market, causing stagnation in client-side scripting. However, in 2004, Mozilla's release of Firefox challenged Internet Explorer's dominance and gained significant market share. Mozilla joined ECMA International in 2005 and collaborated with Macromedia (later Adobe Systems) to standardize ActionScript 3 as the new ECMAScript 4.