JavaScript has only one type of numbers.
Numbers can be written with, or without decimals:
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:
var y = 123e5;      // 12300000 var z = 123e-5;     // 0.00123
You will learn more about numbers later in this tutorial.