select random number from 1 to 4 in js code example

Example 1: javascript random number between 1 and 10

// Genereates a number between 0 to 1;
Math.random();

// to gerate a randome rounded number between 1 to 10;
var theRandomNumber = Math.floor(Math.random() * 10) + 1;

Example 2: math random from minus 1

var plusOrMinus = Math.random() < 0.5 ? -1 : 1;