rgb转16进制

String.prototype.colorHex = function () {
  // RGB颜色值的正则
  var reg = /^(rgb|RGB)/;
  var color = this;
  if (reg.test(color)) {
    var strHex = "#";
    // 把RGB的3个数值变成数组
    var colorArr = color.replace(/(?:(|)|rgb|RGB)*/g, "").split(",");
    // 转成16进制
    for (var i = 0; i < colorArr.length; i++) {
      var hex = Number(colorArr[i]).toString(16);
      if (hex === "0") {
        hex += hex;
      }
      strHex += hex;
    }
    return strHex;
  } else {
    return String(color);
  }
};