Question

How do I show a message from the php action script of a form?

The form is a user login with these fields.

<div id="register_user_box" class="inline_form" style="position: absolute; top: 20px; right: 10px; <br/>
     <span id="user_msg"></span><br/>
     <form action="register_user.php" method="post"> 
     <input type="hidden" name="id" id="id" value="add" /> 
     <input type="hidden" name="edit_user" id="edit_user" value="y" />
     <table cellspacing="0px"> <tr><td>Username:</td></tr><tr><td>
     <input type="text" name="uname" size="30" value="" class="inline_input"/></td> </tr> <tr><td>Email:</td></tr><tr><td>
     <input type="text" name="uemail" size="30" value="" class="inline_input"/></td> </tr> <tr><td>Password:</td></tr><tr><td>
     <input type="password" name="upass" size="30" class="inline_input"/></td> </tr> <tr><td>Confirm Password:</td></tr><tr> <td> 
     <input type="password" name="cpass" size="30" class="inline_input"/></td></tr> </table></td></tr> </table> <p>
     <input class="button" type="submit" name="register" value="Register" style="float:right;"/></p>     
     </form>
</div>

The php script register_user.php checks the if the passwords match and shows an error message if they don’t. The script checks all the other fields and prints a message if necessary.

<?php

    $messages = array( 'usr_cred_req' => 'Must specify username, email, password.',
                        'usr_name_bad' => 'Bad username selection.  Select a different usrename.', 
                        'usr_name_exists' => 'Username selected already exists.  Select a different username.',
                        'usr_email_bad' => 'Bad email selection.  Select a different email.',
                        'usr_email_exists' => 'Email selected already exists.  Select a different email.',
                        'usr_pass_notmached' => 'Passwords do not match.  Type passwords again.', 
                        'usr_not_added' => 'User not added.',
                        'usr_not_updated' => 'User not updated.',
                        'usr_added' => 'User added.'
                        );

    $username = trim($_REQUEST['uname']);
    $email = trim($_REQUEST['uemail']);
    $password = md5(trim($_REQUEST['upass']));
    $copasswd = md5(trim($_REQUEST['cpass']));


    if ( $password != $copasswd ) { echo '<script> $("#usr_msg").html("'.$messages['usr_pass_notmached'].'"); </script>'; return;}
?>

The error message isn’t shown and the browser leaves the page. I’d like the browser to stay on the page and add the error message to the span user_msg.

Answer 1

If you don’t want the browser to leave the page when the form is submitted, then you will have to use AJAX to submit the form in the background to communicate with the server and then update the container with the error message (or something different on success).

Alternatively, have the PHP form post to itself, check the error messages before you output your HTML and if there was an error, insert the error message in the form markup in the desired location and re-populate the form with all of the values that were originally submitted.