Q. What is typeof operator?

JavaScript provides a typeof operator that can examine a value and tell you what type it is:

var a;
typeof a;				// "undefined"

a = "hello world";
typeof a;				// "string"

a = 42;
typeof a;				// "number"

a = true;
typeof a;				// "boolean"

a = null;
typeof a;				// "object" -- weird, bug

a = undefined;
typeof a;				// "undefined"

a = { b: "c" };
typeof a;				// "object"