javascript实现rgb颜色转换成16进制格式

function zero_fill_hex(num, digits) { var s = num.toString(16); while (s.length < digits)  s = "0" + s; return s;}function rgb2hex(rgb) { if (rgb.charAt(0) == '#')  return rgb;  var ds = rgb.split(//D+/); var decimal = Number(ds[1]) * 65536 + Number(ds[2]) * 256 + Number(ds[3]); return "#" + zero_fill_hex(decimal, 6);}