JS: Returns a random number between min and max

gistfile1.js

/**
 * Returns a random number between min and max
 * @param min in range              [default 1]
 * @param max in range              [default 100]
 * @dec decimal places for result   [default 2]
 * 
 * @return float
 */
function getRandomArbitary (min, max, dec) {
    
    dec = typeof dec !== 'undefined' ? dec : 2;
    min = typeof min !== 'undefined' ? min : 1;
    max = typeof max !== 'undefined' ? max : 100;
    
    return parseFloat((Math.random() * (max - min) + min).toFixed(dec));
    
}