javascript实现十六进制颜色值（HEX）和RGB格式相互转换

//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).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+aNum);

            }

            return numHex;

        }

    }else{

        return that;        

    }};

 /*16进制颜色转为RGB格式*/

 String.prototype.colorRgb = function(){

    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 "RGB(" + sColorChange.join(",") + ")";

    }else{

        return sColor;        

    }};

ar sRgb = "RGB(23, 245, 56)" , sHex = "#34538b";

var sHexColor = sRgb.colorHex();

var sRgbColor = sHex.colorRgb();