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();