資料型別
JavaScript 變數可以包含許多資料型別:數字,字串,陣列,物件等:
// Number
var length = 16;
// String
var message = "Hello, World!";
// Array
var carNames = ['Chevrolet', 'Nissan', 'BMW'];
// Object
var person = {
firstName: "John",
lastName: "Doe"
};
JavaScript 具有動態型別。這意味著同一個變數可以用作不同的型別:
var a; // a is undefined
var a = 5; // a is a Number
var a = "John"; // a is a String