js 浮点数加、减、乘、除。

 1.浮点数加法运算
    function numAdd(arg1, arg2) {
        var r1, r2, m;
        try {
            r1 = arg1.toString().split(".")[1].length
        } catch (e) {
            r1 = 0
        }
        try {
            r2 = arg2.toString().split(".")[1].length
        } catch (e) {
            r2 = 0
        }
        m = Math.pow(10, Math.max(r1, r2));
        return (arg1 * m + arg2 * m) / m;
    }

2.浮点数减法运算
    function FloatSub(arg1, arg2) {
        var r1, r2, m, n;
        try {
            r1 = arg1.toString().split(".")[1].length
        } catch (e) {
            r1 = 0
        }
        try {
            r2 = arg2.toString().split(".")[1].length
        } catch (e) {
            r2 = 0
        }
        m = Math.pow(10, Math.max(r1, r2));
        //动态控制精度长度
//        n = (r1 = r2) ? r1 : r2;
        return (arg1 * m - arg2 * m) / m;
    }

3.浮点数乘法运算
    function FloatMul(arg1, arg2) {
        var m = 0, s1 = arg1.toString(), s2 = arg2.toString();
        try {
            m += s1.split(".")[1].length
        } catch (e) {
        }
        try {
            m += s2.split(".")[1].length
        } catch (e) {
        }
        return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
    }

4.浮点数除法运算
    function FloatDiv(arg1, arg2) {
        var t1 = 0, t2 = 0, r1, r2;
        try {
            t1 = arg1.toString().split(".")[1].length
        } catch (e) {
        }
        try {
            t2 = arg2.toString().split(".")[1].length
        } catch (e) {
        }
        with (Math) {
            r1 = Number(arg1.toString().replace(".", ""));
            r2 = Number(arg2.toString().replace(".", ""));
            return (r1 / r2) * pow(10, t2 - t1);
        }
    }