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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">​​​​​​​

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">​​​​​​​

• javascript
• html

Share Improve this question Follow edited Sep 16, 2012 at 17:49 A.M.K 16.8k44 gold badges3535 silver badges6464 bronze badges asked Sep 16, 2012 at 17:27 user1666411user1666411 33522 gold badges77 silver badges1111 bronze badges 1

• Check your assumptions again. – user166390 Commented Sep 16, 2012 at 17:30

Add a ment  | 

2 Answers 2

Sorted by: Reset to default 13

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 plete 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.

When returning false, you prevent the form from being submitted. Otherwise, the form would be submitted, even though it may have validation errors, e.g., the feed value was empty.

On the other hand, if you return true, the form data will be submitted to the URL defined by the action attribute.

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