What can JavaScript do?

Examples Explained


Where to Insert JavaScript

Where to Explained


JavaScript Output

Output Explained


JavaScript Syntax

Syntax Explained



JavaScript Statements

Statements Explained


JavaScript Comments

Comments Explained


JavaScript Variables

Variables Explained


JavaScript Arithmetic

Arithmetic Explained


JavaScript Assignment

Assignment Explained


JavaScript String Concatenation

Concatenation Explained


JavaScript Data Types

Data types Explained


JavaScript Objects

Objects Explained


JavaScript Functions

Functions Explained


JavaScript Events

Events Explained


JavaScript Strings

Strings Explained


JavaScript Numbers

Numbers can be written with or without decimalsExtra large or extra small numbers can be written with exponent notationNumber are considered accurate only up to 15 digitsFloating point arithmetic is not always 100% accurateBut it helps to multiply and divide by 10Adding two numbers results in a new numberAdding two numeric strings results in a concatenated stringAdding a number and a numeric string also results in a concatenated stringAdding a numeric string and a number also results in a concatenated stringCommon mistake when adding strings and numbers 1Common mistake when adding strings and numbers 2JavaScript will try to convert strings to numbers when dividingJavaScript will try to convert strings to numbers when multiplyingJavaScript will try to convert strings to numbers when subtractingJavaScript will NOT convert strings to numbers when addingA number divided by a string is NaN (Not a Number)A number divided by a numeric string is a numberThe global JavaScript function isNaN() returns if a value is a numberUsing NaN in a mathematical operation will always return NaNUsing NaN in a mathematical string operation will concatenate NaNNaN (Not a Number) is a number (Yes! typeof NaN returns number)Infinity is returned if you calculate a number outside the largest possible numberDivision by zero also generates InfinityInfinity is a number (typeof Infinity returns number)Constants, preceded by 0x, are interpreted as hexadecimalThe toString() method can output numbers as hex, octal, and binaryNumbers can be objectsNumbers and objects cannot be safely comparedObjects and objects cannot be safely compared

Numbers Explained


JavaScript Number Methods

Numbers Methods Explained


JavaScript Maths

Maths Explained


JavaScript Random

Random Explained


JavaScript Dates

Dates Explained


JavaScript Arrays

Arrays Explained


JavaScript Array Methods

Array Methods Explained


JavaScript Array Sort

Array Sort Explained


JavaScript Array Iteration

Array Iteration Explained


JavaScript Type Conversion

Type Conversion Explained


JavaScript Booleans

Booleans Explained


JavaScript Comparisons

Comparisons Explained


JavaScript Conditionals

Conditionals Explained


JavaScript Loops

Loops Explained


JavaScript Error Handling

Errors Explained


JavaScript Regular Expressions


JavaScript Objects

Objects Explained


JavaScript Object Properties

Object Properties Explained


JSON Objects

JSON Object Properties Explained


JSON Arrays

JSON Arrays Explained


JSON Parse

JSON Parse Explained


JSON Stringify

JSON Stringify Explained


JSON PHP

JSON PHP Explained


JSON HTML

JSON HTML Explained


JSON JSONP

JSON JSONP Explained