Question

I have this code where i validate each field to be not empty and the problem is that when every field is filled I have to press submit twice in order for the form to be submitted.

<table>
    <form method ="post" <?php 
    if(!empty($_POST['Firstname']) &&
       !empty($_POST['Lastname']) &&
       !empty($_POST['Email']) &&
       !empty($_POST['Comments'])){
       echo 'action="messagesent.php"';}
     else if(isset($_POST['Firstname']) ||
       isset($_POST['Lastname']) ||
       isset($_POST['Email']) ||
       isset($_POST['Comments'])) {
       echo 'action="contact.php"';}?> >
        <tr>
        <td><label>Firstname:</td><td><input name ="Firstname" type ="text" size ="30" <?php if(!empty($_POST['Firstname'])){$Firstname=$_POST['Firstname'];echo "value=$Firstname";} ?> /></td><td><?php if(empty($_POST['Firstname'])){echo "<font color='blue'>*</font>";}?></td>
        </tr>

        <tr>
        <td><label>Lastname:</td><td><input name="Lastname" type ="text" size ="30" <?php if(!empty($_POST['Lastname'])){$Lastname = $_POST['Lastname'];echo "value=$Lastname";}?> /></td><td><?php if(empty($_POST['Lastname'])){echo "<font color='blue'>*</font>";}?></td>
        </tr>

        <tr>
        <td><label>E-mail:</td><td><input name="Email" type ="text" size ="30" <?php if(!empty($_POST['Email'])){$Email = $_POST['Email'];echo "value=$Email";}?> /></td><td><?php if(empty($_POST['Email'])){echo "<font color='blue'>*</font>";}?> </td>
        </tr>

        <tr>
        <th colspan="2"><label>Your Message</th>
        </tr>
        <tr>
        <td colspan="2"><textarea name= "Comments" rows="10" cols="34"><?php $Comments=$_POST['Comments'];if(!empty($_POST['Comments'])){echo "$Comments";} ?> </textarea></td><td><?php if(empty($_POST['Comments'])){echo "<font color='blue'>*</font>";}?> </td>
        </tr>
        <tr>
        <td><input type="submit" value = "SUBMIT"/> </td>
        </tr>

    </form>
</table>

Answer 1

It looks like you’re expecting PHP to check whether the fields on the page are filled in. That’s not how PHP works. It evaluates once, when the page is first rendered, and then never does anything again until the page is loaded again. PHP’s $_POST array doesn’t refer to the input fields on the page; it refers to the values that the page received from the form when it was loaded. So what’s happening is;

1. The page loads for the first time, and $_POST is empty because no form was submitted.
2. PHP sees this and sets ACTION to send you back to the same page.
3. You fill in the form and hit submit.
4. The page reloads, but this time $_POST has values in it because you just submitted the form.
5. PHP sees the values in $_POST and sets ACTION to send you to the next page.
6. You fill in the form again, hit submit, and get sent to the next page.

If you want to check the form to see if the fields are filled in before the form is submitted, you can’t use PHP. You’ll need to use some javascript. Here’s a quick tutorial, where the first example addresses what you’re looking for.