Variables store values such as text, numbers, or objects. Variables are either declared and then later set, or can be set when they are declared.

var myNumber; //declaring but not setting
var myNumber = 93;//setting when you declare

You can set variables like so:

var myNumber = 1;

or

var welcomeMessage = 'This is a string';

Variables can also be HTML objects by using document.getElementById.

var header = document.getElementById("header");

Where the part in quotes is the id of the object you want to access.

You can set part of your HTML to a variable’s value by using the document.innerHTML command.

document.getElementById('myId').innerHTML="joeybabcock.me";

(note this uses getElementById, which we will get into better detail later)

In addition, variables can even be other variables combined.

var y = 1;

var z = 2;

var x = y + z;

x would equal 3.

Click Here for a more in depth tutorial of innerHTML and getElementById, in Part 3.