Form validation for zip codes

Question

I have a function that I intend to use for validating zip codes and I wanted to know if my way could be made better.

function zipcode (inputtxt)    
{  
    var zipcode = /^\+?([0-9]{2})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})$/;  

    if((inputtxt.value.match(zipcode))  
        {  
          return true;  
        }  
        else  
        {  
            alert("message");  
            return false;  
        }  
}  

Answer 1

Changes I would make: (but not necessary)

• Make sure inputtext has a value, and isn't undefined, so it wouldn't throw an error in your if statement.
• Replace the if statement with return instead. (This is mostly to minimize the code a bit, something your minifier won't do for you).

Except for that, it seems ok (I'm not looking into the logic of the regex, since I'm not sure how a zipcode should be parsed).

function zipcode (inputtxt)    
{  

    if (!inputtxt || !inputtxt.value) return false;
    var zipcode = /^\+?([0-9]{2})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})$/;  

    return ((inputtxt.value.match(zipcode));
} 

Answer 2

Um. There is verry little code, so one can not say much about your code. It does, what it should, I assume.

One thing, I see is, that you are alerting a message, which has nothing to do with the validation. So if you are looking for SRP - the separation of concerns, you take the alert out and put it elsewhere.

Of course you could shrink the whole thing down to

function checkZipcode(zip) {
    if(!zip) throw new TypeError("zip is not defined"); 
    return /^\+?([0-9]{2})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})$/.test(zip); 
}

done. But whether this is an improvement or not is open.