Radius of the circle:
Perimeter of the circle:
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
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.