开发过程遇到的问题

• js计算精度问题
• ie下forEach不支持问题
• 数组去重复问题

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<script type="text/javascript">
        //解决js计算精度
        function add(a, b) {
            var c, d, e;
            try {
                c = a.toString().split(".")[1].length;
            } catch (f) {
                c = 0;
            }
            try {
                d = b.toString().split(".")[1].length;
            } catch (f) {
                d = 0;
            }
            return e = Math.pow(10, Math.max(c, d)), (mul(a, e) + mul(b, e)) / e;
        }
        function sub(a, b) {
            var c, d, e;
            try {
                c = a.toString().split(".")[1].length;
            } catch (f) {
                c = 0;
            }
            try {
                d = b.toString().split(".")[1].length;
            } catch (f) {
                d = 0;
            }
            return e = Math.pow(10, Math.max(c, d)), (mul(a, e) - mul(b, e)) / e;
        }

        function mul(a, b) {
            var c = 0,
        d = a.toString(),
        e = b.toString();
            try {
                c += d.split(".")[1].length;
            } catch (f) { }
            try {
                c += e.split(".")[1].length;
            } catch (f) { }
            return Number(d.replace(".", "")) * Number(e.replace(".", "")) / Math.pow(10, c);
        }

        function div(a, b) {
            var c, d, e = 0,
        f = 0;
            try {
                e = a.toString().split(".")[1].length;
            } catch (g) { }
            try {
                f = b.toString().split(".")[1].length;
            } catch (g) { }
            return c = Number(a.toString().replace(".", "")), d = Number(b.toString().replace(".", "")), mul(c / d, Math.pow(10, f - e));
        }
        //取数组重复
        function uniArr(arr) {
            var new_arr = [];
            for (var i = 0; i < arr.length; i++) {
                var items = arr[i];
                if ($.inArray(items, new_arr) == -1) {
                    new_arr.push(items);
                }
            }
            return new_arr;
        }

        //ie版本forEach不支持问题
        Array.prototype.forEach = function forEach(callback, thisArg) {
            var T, k;
            if (this == null) {
                throw new TypeError("this is null or not defined");
            }
            var O = Object(this);
            var len = O.length >>> 0;
            if (typeof callback !== "function") {
                throw new TypeError(callback + " is not a function");
            }
            if (arguments.length > 1) {
                T = thisArg;
            }
            k = 0;

            while (k < len) {

                var kValue;
                if (k in O) {

                    kValue = O[k];
                    callback.call(T, kValue, k, O);
                }
                k++;
            }
        };
    </script>

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