String function that converts a hex value (#FFFFFF) into an rgba value.

string.hex2rgba.js

/**
 * HEX TO RGBA
 * Convert a hex string for colors into an rbga value
 *
 * @param alpha (float) THe opacity value of the color
 **/
String.prototype.hexToRgbA = function(alpha) {
    var c;
    if(/^#([A-Fa-f0-9]{3}){1,2}$/.test(this)){
        c= this.substring(1).split('');
        if(c.length== 3){
            c= [c[0], c[0], c[1], c[1], c[2], c[2]];
        }
        c= '0x'+c.join('');
        return 'rgba('+[(c>>16)&255, (c>>8)&255, c&255].join(',')+','+(alpha ? alpha : 1)+')';
    }

    throw new Error('Bad Hex');
};