Rerender Html page after PHP function call

Question

I currently have this login page.

<form action='http://localhost:8080/iSchedj/API/api.php' method='post'>
<fieldset>

<p>
<label for='username'>Username</label>
<input type='text' id='username' name='username' value='' maxlength='20' />
</p>

<p>
<label for='password'>Password</label>
<input type='password' id='password' name='password' value='' maxlength='40' />
</p>

<p>
<input type='hidden' name='form_token' value='<?php echo $form_token; ?>' />
<input type='submit' name='login' id='login' value='Login' />
</p>

</fieldset>
</form>

On submit, I have a function on the server-side where I analyze the data and check if there are any issues.

Problem is, I would like to send a response back to the client and re render the login page if any issues occurred with a response saying 'Error on login'.

I am having an issue with the response part.

On the server side, I just run this when an error is found in the form header( 'Location: http://localhost:8080/iSchedj/index.php'); echo 'Incorrect Length for Password';

which redirects the client to the login page. But how do I send the error message to the page as well? The echo message is no where to be found.

Answer 1

Add it to the URL and display your error message via JavaScript.

header( 'Location: http://localhost:8080/iSchedj/index.php#error=1');

Your JS script will need to look at the document.location.hash and behave accordingly.