option spread calculation

optionspread.js

var calc = function (itm_percent, credit_received, spread_with, multiplier) {
    var win = 0;
    var lose = 0;

    for (var m = 0; m < multiplier; m++) {
        for (var i = 0; i < 100; i++) {
            // 0 -> 99
            var r = Math.floor(Math.random() * 100);

            if (r < itm_percent) win++;
            if (r >= itm_percent) lose++;
        }
    }

    var gain = win * credit_received;
    var loss = lose * (spread_with - credit_received);

    return { 
        "winners": win, 
        "winrate" : win / (multiplier * 100), 
        "gain": gain,
        "losers": lose, 
        "lossrate" : lose / (multiplier * 100), 
        "loss": loss,
        "profit" : gain - loss
    };
}

calc(80, 20, 100, 1);