js 实现两个小数的相乘、相除、相加和相减功能

<script type="text/javascript">
//两数相加
    function numadd(a, b) {
    
        a = isNaN(a) ? 0 : a
        b = isNaN(b) ? 0 : 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)), (nummul(a, e) + nummul(b, e)) / e;
    }

    //两数相乘
    function nummul(a, b) {
    
        a = isNaN(a) ? 0 : a
        b = isNaN(b) ? 0 : b
        var c = 0,
            d = a.toString(),
            e = b.toString();
        try {
    
            c += d.split(".")[1].length;
        } catch (f) {
    
            f == f
        }
        try {
    
            c += e.split(".")[1].length;
        } catch (f) {
    
            f == f
        }
        return Number(d.replace(".", "")) * Number(e.replace(".", "")) / Math.pow(10, c);
    }

    //两数相减
   function numsub(a, b) {
    
        a = isNaN(a) ? 0 : a
        b = isNaN(b) ? 0 : 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)), (nummul(a, e) - nummul(b, e)) / e;
    }

    /** * 两数相除 * @param a 被除数 * @param b 除数 * @returns {*} */
    function numdiv(a, b) {
    
        a = isNaN(a) ? 0 : a
        b = isNaN(b) ? 0 : b
        var c, d, e = 0,
            f = 0;
        try {
    
            e = a.toString().split(".")[1].length;
        } catch (g) {
    
            g == g
        }
        try {
    
            f = b.toString().split(".")[1].length;
        } catch (g) {
    
            g == g
        }
        return c = Number(a.toString().replace(".", "")), d = Number(b.toString().replace(".", "")), nummul(c / d, Math.pow(10, f - e));
    }
	 $(function(){
    
		alert(numadd(1.414,1.732));
		alert(nummul(1.732,1.4146));
		alert(numsub(1.414,1.732));
		alert(numdiv(1.732,1.4146));
	});
</script>