Validation on a JS function

Question

I have a list of people that are being added via a search. Everything works, but there's one case where if you don't select a person from this list, you get an ugly 400 page. Obviously it's because I'm not handling the validation there.

My "remove from list" button is done this way:

<input type="button" value="Remove" onclick="delTeamNominee(document.f.teamList.value)"/>

Here's my function:

function delTeamNominee(id) {
    document.dl.empId.value = id;
    document.dl.submit();        
}

dl is a hidden form that executes a Spring MVC method:

 <form name="dl" action="teamDeleteEmployee" method="post">
    <input type="hidden" name="empId">
</form>

Obviously I would like to do something like this:

function delTeamNominee(id) {
    if (id == null) {
         alert("You must select a person");
    } else {
         document.dl.empId.value = id;
         document.dl.submit();
    }
}

Which of course, doesn't work.

score 1 · Accepted Answer · answered Apr 20 '12 at 16:16

1

Perhaps you should also check to see if id is undefined. Something like the following will catch both null and undefined:

if (!id) { .... }

answered Apr 20 '12 at 16:16

dgabriel

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1

0 is also considered to be falsey, and would evaluate as such in that if statement. See http://stackoverflow.com/a/1998224/17803 – Matt Apr 20 '12 at 16:28
Thanks, that was exactly what was missing. – Nimchip Apr 20 '12 at 16:28

Validation on a JS function

1 Answers1