封装js加、减、乘、除方法

1. 加法

function accAdd(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. 减法

function accSubtr(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).toFixed(n);
} 

3. 乘法

function accMul(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. 除法

function accDivCoupon(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);
    }
}