Question

i dont quite understand how the onsubmit="return validate()" works.
why do i have to return the function? does this work only when it detects a return false from the statement?

<script type="text/javascript">
    function validate() {
        if ((document.example2.naming.value == "") || (document.example2.feed.value == "")) {
            alert("You must fill in all of the required .fields!");
            return false;
        }
        else {
            return true;
        }
</script>

<form name="example2" onsubmit="return validate()">
<input type="submit" name="B1" value="Submit">​​​​​​​

Answer 1

Using return for onsubmit determines whether the form actually submits or not (true or false, respectively). This is useful for Javascript when you want to do something specific before allowing the form to submit or not. For example, like the code you provided, the point is to stop the form from submitting if the form isn’t valid – if a certain field is blank. The important part is that you need to include return in the onsubmit part, as well as actually returning true or false in the function you call. This is because the behavior for onsubmit is to always complete unless you return false. So when you do something like:

onsubmit="validate();"

nothing is returned (because of the lack of return) – so the function is run but that’s it, so the form is submitted. When you add return, then the submitting depends on the return value – what’s returned from the function. If you don’t use return, it doesn’t matter what the validate function returns, because the result of validate is not actually returned to onsubmit.