Comparing two JavaScript methods to see which one is faster.

gistfile1.js

startTimer = function() {
    var start = new Date().getTime();
    return start;
};

stopTimer = function(start) {
    var end = new Date().getTime();
    var time = end - start;
    return time;
};

functionA = function(x, y, velocity) {
    var distance_x = x + 0; // replaced this.pos.x + this.size.x/2 with zero
    var distance_y = y + 0; // replaced this.pos.x + this.size.x/2 with zero
    var velocityX = (distance_x > 1 ? 1 : -1) * velocity * (Math.abs(distance_x) / (Math.abs(distance_x) + Math.abs(distance_y)));
    var velocityY = (distance_y > 1 ? 1 : -1) * velocity * (Math.abs(distance_y) / (Math.abs(distance_x) + Math.abs(distance_y)));
    return {
        x: velocityX,
        y: velocityY
    };
};

functionB = function(x, y, velocity) {
    var centerX = 0; // replaced this.pos.x + this.size.x/2 with zero
    var centerY = 0; // replaced this.pos.x + this.size.x/2 with zero
    var angleToTarget = Math.atan2(y - centerY, x - centerX);
    var velocityX = Math.cos(angleToTarget) * velocity;
    var velocityY = Math.sin(angleToTarget) * velocity;
    return {
        x: velocityX,
        y: velocityY
    };
};

var total_time_a = 0;
var total_time_b = 0;
var start, end, time, x, y, velocity, result;
for (var i = 0; i < 1000000; i++) {

    // Generate random x, y, and velocity values.
    x = Math.floor(Math.random() * 100000);
    y = Math.floor(Math.random() * 100000);
    velocity = Math.floor(Math.random() * 100000);

    // Time method A.
    start = startTimer();
    result = functionA(x, y, velocity);
    time = stopTimer(start);
    total_time_a += time;

    // Time method B.
    start = startTimer();
    result = functionB(x, y, velocity);
    time = stopTimer(start);
    total_time_b += time;
}

var winner = (total_time_a < total_time_b ? 'Method A' : 'Method B');
var speed_factor = Math.max(total_time_a, total_time_b) / Math.min(total_time_b, total_time_a);
var text = 'Winner: ' + winner + "\n" + 'It was ' + speed_factor.toFixed(2) + ' times faster.';

document.write('DONE! ');
document.write(text);