js check amount

// any positive integer, positive decimals (no more than two decimal places)

There is not I = / ^ (([1-9] [0-9] *) | (([0] \. \ d {1,2} | [1-9] [0-9] * \. \ d {1,2}))) $ /;

There num = "666.62";

 if(isNum.test(num)) {

   return true;

}

// verify the amount (including zero), two decimal places

 var reg = /(^[1-9]([0-9]+)?(\.[0-9]{1,2})?$)|(^(0){1}$)|(^[0-9]\.[0-9]([0-9])?$)/;
    if (reg.test(num)) {
       return true;
    }

// validate positive integer including 0

 var reg = /^([1-9]\d*|[0]{1,1})$/;
    if (reg.test(num)) {
        return true;
    }