Parses a legacy html color

process-legacy-html-color.js

// processColor processes a legacy html color
// The legacy html colors apply only to colors in the bgcolor attribute
//
// Copyright 2017 Patrick G
// Based on http://scrappy-do.blogspot.ca/2004/08/little-rant-about-microsoft-internet.html
// Also see https://stackoverflow.com/questions/8318911/why-does-html-think-chucknorris-is-a-color
function processColor(color) {
    // Remove the hash
    color = color.replace("#", "");

    // Convert to lowercase
    color = color.toLowerCase()

    // Replace all non-hex chars with a zero
    color = color.replace(/[^A-Fa-f0-9]/g, "0")

    if (color.length < 3) {
        // Append zeros until length is 3
        while (color.length != 3) {
            color = color + "0";
        }
    } else if (color.length == 3) {
        // Prepend a zero before each character
        color = "0" + color.split("")[0] + "0" + color.split("")[1] + "0" + color.split("")[2]
    } else if (color.length > 3) {
        // Append zeros until length is divisible by 3
        while (color.length % 3 != 0) {
            color = color + "0";
        }
    }

    // Split into 3 even chunks (for red, green, blue)
    var rgbHex = [];
    var chunkSize = color.length / 3;
    for (var i = 0; i < color.length; i += chunkSize) {
        rgbHex.push(color.substring(i, i + chunkSize));
    }

    // For each chunk
    for (var i = 0; i < rgbHex.length; i++) {
        // Until length is 2
        while (rgbHex[i].length != 2) {
            if (rgbHex[i].length > 8) {
                // If length is greater than 8, remove first char
                rgbHex[i] = rgbHex[i].substring(1);
            } else {
                // If length is less than 8, remove last char
                rgbHex[i] = rgbHex[i].substring(0, rgbHex[i].length - 1);
            }
        }
    }

    // Add the hash symbol again to make the color
    color = "#" + rgbHex.join("");

    return color;
}