Simple form validation

Question

POST #1

How can I validate this simple form (checking for empty field strings)?

                
Please select your Gift Certificate amount below         


        

Answer 1

Give your form a name (GiftForm)

    <script type="text/javascript">
    function validate_form ( )
    {
        valid = true;

        if ( document.GiftForm.os1.value == "" )
        {
            alert ( "Please fill in the 'Your Name' box." );
            valid = false;
        }

        return valid;
    }
</script>

Answer 2

A couple of hints that should get you going.

Add a submit event handler:

<form action="https://www.paypal.com/cgi-bin/webscr" method="post" onsubmit="return validate()">

Give IDs to the input fields you want to get.

<input id="currency_code" type="hidden" name="currency_code" value="CAD">

Write the validation code, return false if you don't want to submit.

<script type="text/javascript">

    function validate() {

        var currencyCode = document.getElementById("currency_code");

        var ok = currencyCode.value !== '';

        return ok;

    }

</script>

Answer 3

Is jQuery an option? There's a really nice Validation tool http://docs.jquery.com/Plugins/Validation

Answer 4

Here is a simple tutorial along with demo and source code, I hope this works for you, all the best! http://gonga.in/simple-javascript-form-validation/