HTML form action and onsubmit issues

Question

I want to run JavaScript user validation on some textbox entries.

The problem I'm having is that my form has the action of going to a new page within our site, and the onsubmit attribute never runs the JavaScript function.

Is there a better solution, or one that works with the following code: Note: the JavaScript file is written correctly and works if you switch the action to checkRegistration().

It is merely an issue with running both action and JavaScript.

<form name="registerForm" action="validate.html" onsubmit="checkRegistration()" method="post">
    <!-- Textboxes are here -->
    <!-- And the submit button -->
</form>

Answer 1

You should stop the submit procedure by returning false on the onsubmit callback.

<script>
    function checkRegistration(){
        if(!form_valid){
            alert('Given data is not correct');
            return false;
        }
        return true;
    }
</script>

<form onsubmit="return checkRegistration()"...

Here you have a fully working example. The form will submit only when you write google into input, otherwise it will return an error:

<script>
    function checkRegistration(){
        var form_valid = (document.getElementById('some_input').value == 'google');
        if(!form_valid){
            alert('Given data is incorrect');
            return false;
        }
        return true;
    }
</script>

<form onsubmit="return checkRegistration()" method="get" action="http://google.com">
    Write google to go to google...<br/>
    <input type="text" id="some_input" value=""/>
    <input type="submit" value="google it"/>
</form>