Random number in range

math_random.js

/**
 * Returns a random number between min and max
 */
function getRandomArbitary (min, max) {
    return Math.random() * (max - min) + min;
}

/**
 * Returns a random integer between min and max
 * Using Math.round() will give you a non-uniform distribution!
 */
function getRandomInt (min, max) {
    return ~~(Math.random() * (max - min + 1)) + min; // ~~ equals Math.floor
}