In Firebug''s console

var a = [];
a[0] = a;

crashed Firefox!

Why?

edit:

1. This statement is logically correct, and there is nothing bad about referencing recursion. Therefor it''s a bug in browser Firebug.
2. Works fine in Chrome and Opera.
3. I''m using last official versions of Firebug and Firefox

edit 2: It crashes in Firebug console and works in native Firefox web console