Loosely typed

Loosely typed

Javascript is a loosely typed language, the type of variable is not define when it is declared, but when it is assigned value to.

console.log(typeof x); // undefined

var x;
console.log(typeof x); // undefined
console.log(x); // undefined

x = null;
console.log(typeof x); // object
console.log(x); //null

x = "hello";
console.log(typeof x); // string

x = 123;
console.log(typeof x); // number

x = 123.34;
console.log(typeof x); // number

x = true;
console.log(typeof x); // boolean

x = function(){};
console.log(typeof x); // function