Js 实现十六进制颜色值和RGB颜色值转换整理

        var colorChange = {
            rgbToHex: function (val) {  //RGB(A)颜色转换为HEX十六进制的颜色值
                var r, g, b, a,
                    regRgba = /rgba?\((\d{1,3}),(\d{1,3}),(\d{1,3})(,([.\d]+))?\)/,    //判断rgb颜色值格式的正则表达式，如rgba(255,20,10,.54)
                    rsa = val.replace(/\s+/g, '').match(regRgba);
                if (!!rsa) {
                    r = parseInt(rsa[1]).toString(16);
                    r = r.length == 1 ? '0' + r : r;
                    g = (+rsa[2]).toString(16);
                    g = g.length == 1 ? '0' + g : g;
                    b = (+rsa[3]).toString(16);
                    b = b.length == 1 ? '0' + b : b;
                    a = (+(rsa[5] ? rsa[5] : 1)) * 100;
                    return { hex: '#' + r + g + b, r: parseInt(r, 16), g: parseInt(g, 16), b: parseInt(b, 16), alpha: Math.ceil(a) };
                } else {
                    return { hex: '无效', alpha: 100 };
                }
            },
            hexToRgb: function (val) {   //HEX十六进制颜色值转换为RGB(A)颜色值
                // 16进制颜色值的正则
                var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
                // 把颜色值变成小写
                var color = val.toLowerCase();
                var result = '';
                if (reg.test(color)) {
                    // 如果只有三位的值，需变成六位，如：#fff => #ffffff
                    if (color.length === 4) {
                        var colorNew = "#";
                        for (var i = 1; i < 4; i += 1) {
                            colorNew += color.slice(i, i + 1).concat(color.slice(i, i + 1));
                        }
                        color = colorNew;
                    }
                    // 处理六位的颜色值，转为RGB
                    var colorChange = [];
                    for (var i = 1; i < 7; i += 2) {
                        colorChange.push(parseInt("0x" + color.slice(i, i + 2)));
                    }
                    result = "rgb(" + colorChange.join(",") + ")";
                    return { rgb: result, r: colorChange[0], g: colorChange[1], b: colorChange[2] };
                } else {
                    result = '无效';
                    return { rgb: result };
                }
            }
        };