JavaScript实现十六进制颜色值（HEX）和RGB格式相互转换

JavaScript实现十六进制颜色值（HEX）和RGB格式相互转换

在Web开发实践中，常需进行颜色域值格式间的转换，此处提供一种实现方案。

//用于校验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})$/;
/*将RGB颜色字符串转换为16进制格式*/
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;
    }};
/*将16进制颜色值转换为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;
        }
//处理六位颜色值的情况
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;
    }};

调用颜色转换方法的示例：

ar sRgb = "RGB(23, 245, 56)" , sHex = "#34538b";
var sHexColor = sRgb.colorHex();
var sRgbColor = sHex.colorRgb();