var dec = r*g*b; // but this doesn't work

var c = 0xff03c0; // 16712640
var components = {
    r: (c & 0xff0000) >> 16,
    g: (c & 0x00ff00) >> 8,
    b: (c & 0x0000ff)
};

c = (components.r << 16) + (components.g << 8) + (components.b);

'Convert RGB to LONG:
 LONG = B * 65536 + G * 256 + R

'Convert LONG to RGB:
 B = LONG  65536
 G = (LONG - B * 65536)  256
 R = LONG - B * 65536 - G * 256

var dec = (b & 0xff) << 16 + (g & 0xff) << 8 + (r & 0xff);

var dec = r << 16 + g << 16 + b;

if (color.substr(0, 1) === '#') {
    return color;
}
var digits = /(.*?)rgb((d+), (d+), (d+))/.exec(color);
var red = parseInt(digits[2]);
var green = parseInt(digits[3]);
var blue = parseInt(digits[4]);
var rgb = blue | (green << 8) | (red << 16);
return rgb.toString(10);

var rgbTotal = red * 65536 + green * 256 + blue;

var R = Math.trunc( rgbTotal / 65536 );
var G = Math.trunc( ( rgbTotal % 65536 ) / 256 );
var B = rgbTotal % 256;