Global Domination � Yahoo! User Interface Blog

Global Domination � Yahoo! User Interface Blog: "Global Domination
June 1, 2006 at 11:27 am by Douglas Crockford | In Development |

JavaScript, as realized in browsers, is a load-and-go programming language. Programs are delivered to the execution site as text. This is a good fit for the web, which is at its root a text delivery system. The program text is eval‘d, which compiles it into an executable form and then immediately executes it. That execution can leave artifacts in the window’s global object.

The global object is the global namespace that holds the top level functions and global variables. Variables which are not explicitly defined are implied global variables, and their names are also kept in the global object. This was a convenience for the little scripts that Navigator 2 was expected to support. In the decade since NS2, those little scripts have grown into Ajax applications, and the true nature of the global object is revealed:"