Definition

You can think of a variable like a bucket used to hold or store substance, in this the substance to be stored is data to be used within a program.

Use cases and Examples

var x = 1;
var result = 2 +x;
console.log("result contains: ", result);

The above Javascript code has two variables namely x is assigned the value 1 and result to the sum of 2 and x which should be 3;

Summary

Variables usually can store whatever data type is available within the programming language under discussion.