...
It uses JavaScript, so you should become familiar with this language before proceeding with this document. A number of very good guides to JavaScript exist on the Internet – Mozilla Developer Network is arguably the best. Note, however, that most online Javascript guides are aimed at web development - Warzone is most certainly not a web browser, so there is no DOM, no HTML, etc.
I've done some digging in to the JS environment in which your scripts run and posted the results here: What's in the JS environment? and API.
The ECMA-262 implementation (Javascript to you and me) used in Warzone is based on Spidermonkey, the JS engine used in Apple's Safari web browser. For more information on it's native features from a C++ developer perspective, see Nokia's QtScript documentation.
...