1、加深color颜色的值采用rgb计算方式
     num = Math.floor( num * ( 1 – level ));
2、减淡color颜色的值采用rgb计算方式
     num = Math.floor(( 255 – num) * level + num )
3、web安全色采用rgb计算方式
     将num除以51再乘以51分别向下、向上取整，尽兴比较
     tmp1 = Math.floor( num / 51 ) * 51;
     tmp2 = Math.ceil( num / 51 ) *51;
     if(Math.abs( tmp1 – num ) <= Math.abs( tmp2 – num ))
         { num = tmp1; }
     else
         { num = tmp2; }
备注：    
     num指0到255之间的数值
     level指0到1之间的数值

效果图如下：

颜色值相互转换Color（续）-风君雪科技博客
参考：Dron 颜色值操作

详细代码如下：

        var Color = function () {
            //将hex颜色值str转化成rgb数组
            this.HexToRgb = function (str) {
                var r = /^\#?[0-9a-f]{6}$/;
                //test方法检查在字符串中是否存在一个模式，如果存在则返回true，否则返回false
                if (!r.test(str)) return window.alert(“输入错误的hex颜色值”);
                //replace替换查找的到的字符串
                str = str.replace(“#”, “”);
                //match得到查询数组
                var hxs = str.match(/../g);
                for (var i = 0; i < 3; i++) hxs[i] = parseInt(hxs[i], 16);
                return hxs;
            }

            //将rgb颜色值为a,b,c转化成hex颜色值
            this.RgbToHex = function (a, b, c) {
                var r = /^\d{1,3}$/;
                if (!r.test(a) || !r.test(b) || !r.test(c)) return window.alert(“输入错误的rgb颜色值”);
                var hexs = [a.toString(16), b.toString(16), c.toString(16)];
                for (var i = 0; i < 3; i++) if (hexs[i].length == 1) hexs[i] = “0” + hexs[i];
                return “#” + hexs.join(“”);
            }

            //得到hex颜色值为color的加深颜色值，level为加深的程度，限0-1之间
            this.getDarkColor = function (color, level) {
                var r = /^\#?[0-9a-f]{6}$/;
                if (!r.test(color)) return window.alert(“输入错误的hex颜色值”);
                var rgbc = this.HexToRgb(color);
                //floor 向下取整
                for (var i = 0; i < 3; i++) rgbc[i] = Math.floor(rgbc[i] * (1 – level));
                return this.RgbToHex(rgbc[0], rgbc[1], rgbc[2]);
            }

            //得到hex颜色值为color的减淡颜色值，level为减淡的程度，限0-1之间
            this.getLightColor = function (color, level) {
                var r = /^\#?[0-9a-f]{6}$/;
                if (!r.test(color)) return window.alert(“输入错误的hex颜色值”);
                var rgbc = this.HexToRgb(color);
                for (var i = 0; i < 3; i++) rgbc[i] = Math.floor((255 – rgbc[i]) * level + rgbc[i]);
                return this.RgbToHex(rgbc[0], rgbc[1], rgbc[2]);
            }

            //得到hex颜色值为color的web安全色
            this.getWebSafeColor = function (color) {
                var r = /^\#?[0-9a-f]{6}$/;
                if (!r.test(color)) return window.alert(“输入错误的hex颜色值”);
                var rgbc = this.HexToRgb(color);
                for (var i = 0; i < 3; i++) {
                    var q1 = Math.floor(rgbc[i] / 51) * 51;
                    //ceil向上取整
                    var q2 = Math.ceil(rgbc[i] / 51) * 51;
                    //abs绝对值
                    if (Math.abs(q1 – rgbc[i]) <= Math.abs(q2 – rgbc[i])) rgbc[i] = q1;
                    else rgbc[i] = q2;
                }
                return this.RgbToHex(rgbc[0], rgbc[1], rgbc[2]);
            }
        }
主要是对字符串操作、正则表达式的应用结合color颜色值rgb计算方法