js 颜色转换,RGB颜色转换为16进制,16进制颜色转为RGB格式

 颜色转换，RGB颜色转换为16进制,16进制颜色转为RGB格式，可以自己设置透明度。

//十六进制颜色值的正则表达式
var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
/*RGB颜色转换为16进制*/
String.prototype.colorHex = function () {
    var that = this;
    if (/^(rgb|RGB)/.test(that)) {
        var aColor = that.replace(/(?:\(|\)|rgb|RGB)*/g, "").split(",");
        var strHex = "#";
        for (var i = 0; i < aColor.length; i++) {
            var hex = Number(aColor[i]).toString(16);
            if (hex === "0") {
                hex += hex;
            }
            strHex += hex;
        }
        if (strHex.length !== 7) {
            strHex = that;
        }
        return strHex;
    } else if (reg.test(that)) {
        var aNum = that.replace(/#/, "").split("");
        if (aNum.length === 6) {
            return that;
        } else if (aNum.length === 3) {
            var numHex = "#";
            for (var i = 0; i < aNum.length; i += 1) {
                numHex += (aNum[i] + aNum[i]);
            }
            return numHex;
        }
    } else {
        return that;
    }
};
/*16进制颜色转为RGB格式*/
String.prototype.colorRgb = function (opacity) {
    var sColor = this.toLowerCase();
    if (sColor && reg.test(sColor)) {
        if (sColor.length === 4) {
            var sColorNew = "#";
            for (var i = 1; i < 4; i += 1) {
                sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1));
            }
            sColor = sColorNew;
        }
        //处理六位的颜色值
        var sColorChange = [];
        for (var i = 1; i < 7; i += 2) {
            sColorChange.push(parseInt("0x" + sColor.slice(i, i + 2)));
        }
        return "rgba(" + sColorChange.join(",") + "," + opacity + ")";
    } else {
        return sColor;
    }
};


//调用方法：
"#f00".colorHex()  //'#ff0000'
'#f00'.colorRgb(0); //'rgba(255,0,0,0)'