Javascript is a language designed to control the software in which it is embedded. Put another way it is a language designed to script an application. Javascript code always executes within a script context that can add new properties and functions – this is for example how Netscape added browser-specific features familiar to Web developers. (…) One of the primary reasons for the js object was to provide a more powerful interface for the patcher scripting features where you can create connect and move new objects.
From the JavaScriptInMax documentation
