Radius of the circle:
Perimeter of the circle:
Firefox 2, Opera 9, Safari 2, Safari 3.0.2, NS 6.1, NS 6.2, NS 7.0, NS 7.2 and many browsers support the javascript reserved keyword const to declare constants in javascript application.
Reference:
reserved keyword const: "You can create a read-only, named constant
with the const keyword. The syntax of a constant identifier is the same
as for a variable identifier: it must start with a letter or underscore
and can contain alphabetic, numeric, or underscore characters."
Update November 21st 2008:
August 26th 2008 ECMAScript 3.1 proposal suggests object.freeze
instead to "sets the writable attribute to false for every own data
property of the object.". const
as a reserved word is
deleted from ECMAScript 3.1 proposals and drafts.