JavaScript Introduction

What Can JavaScript Do?

JavaScript is the programming language of the web.

It can calculate, manipulate and validate data.

It can update and change both HTML and CSS.

JavaScript Can Change HTML Content

One of many JavaScript HTML methods is getElementById().

The example below "finds" an HTML element (with id="demo"), and changes the element content (innerHTML) to "Hello JavaScript":

Example

document.getElementById("demo").innerHTML = "Hello JavaScript";