How to get color value from gradient by percentage with javascript?

I was able to solve this issue using this function, which is based on the less.js function: http://lesscss.org/functions/#color-operations-mix

function pickHex(color1, color2, weight) {
    var w1 = weight;
    var w2 = 1 - w1;
    var rgb = [Math.round(color1[0] * w1 + color2[0] * w2),
        Math.round(color1[1] * w1 + color2[1] * w2),
        Math.round(color1[2] * w1 + color2[2] * w2)];
    return rgb;
}

I just simply need to pass the two closest color codes from the gradient array and the ratio where the slider handle is located(which can be calculated easily with the help of the slider width). Here is the live example:

http://jsfiddle.net/vksn3yLL/