How to set a javascript var as undefined

Question

Given:

console.log(boo); this outputs undefined

Given:

var boo = 1;
console.log(boo); this outputs 1

Aft

Answer 1

delete boo

Don't use var boo = undefined. undefined is just a variable and if someone sets undefined = "hello" then you'll be getting hello everywhere :)

EDIT:

null wasn't same as undefined. removed that bit.