[5] The Closure Compiler is a tool that attempts to compress and optimize JavaScript code, at the expense of human readability.

The process executes the following steps: It also checks syntax, variable references, and types and warns about common JavaScript pitfalls.

[7] The Closure Compiler is available for use through command line tools: The Closure Compiler Service application provides a form for a user to input a URL pointing to a JavaScript source or enter JavaScript source code in a text box.

[8] An API is available, accessible via POST requests, parameters include: The service is marked as deprecated and will eventually be removed.

It provides cross-browser functions for DOM manipulations and events, Ajax and JSON, as well as more high-level objects such as User Interface widgets and Controls.