JavaScript Objects

JavaScript objects are written with curly braces. Object properties are written as name: value pairs, separated by commas. Example var person = {firstName:”John”, lastName:”Doe”, age:50, eyeColor:”blue”}; The object (person) in the example above has 4 properties: firstName, lastName, age, and eyeColor. You will learn more about objects later in this tutorial.

JavaScript Arrays

JavaScript arrays are written with square brackets. Array items are separated by commas. The following code declares (creates) an array called cars, containing three items (car names): Example var cars = [“Saab”, “Volvo”, “BMW”]; Array indexes are zero-based, which means the first item is [0], second is [1], and so on. You will learn more about arrays later […]

JavaScript Booleans

Booleans can only have two values: true or false. Example var x = 5; var y = 5; var z = 6; (x == y)       // Returns true (x == z)       // Returns false Booleans are often used in conditional testing. You will learn more about conditional testing later in this tutorial.

JavaScript Numbers

JavaScript has only one type of numbers. Numbers can be written with, or without decimals: Example var x1 = 34.00;     // Written with decimals var x2 = 34;        // Written without decimals Extra large or extra small numbers can be written with scientific (exponential) notation: Example var y = 123e5;      // 12300000 var z = 123e-5;     // 0.00123 You will learn more about numbers later in this […]

JavaScript Strings

A string (or a text string) is a series of characters like “John Doe”. Strings are written with quotes. You can use single or double quotes: Example var carName = “Volvo XC60”;   // Using double quotes var carName = ‘Volvo XC60′;   // Using single quots You can use quotes inside a string, as long as they don’t match the quotes surrounding […]