Display form error message on form page - php

Question

I am trying to display php error message on same page as form but unable to print this.
Form is working and error message is also showing up but the problem is only form redirect on another page.
Here is form.php
<form action="contact_mail.php" method="post" name="contact_Form" id="contactform">
<div class="row">
<div class="col-md-12 page_subtitle">Get in Touch</div>
</div>
<div class="row mt-30">
<div class="col-md-12 form-group"><input type="text" value="<?php if (isset($errors['name_co'])): echo $errors; endif; ?>" placeholder="Name" class="form-control" name="name_co" ></div>
</div>
<div class="row">
<div class="col-md-6 form-group"><input type="text" id="txtEmail" value="" placeholder="Email ID" class="form-control" name="email_co" pattern="[a-z0-9._%+-]+#[a-z0-9.-]+\.[a-z]{2,63}$" required /></div>
<div class="col-md-6 form-group"><input type="text" value="" placeholder="Phone Number" class="form-control" name="mobile" pattern="[789][0-9]{9}" required /></div>
</div>
<div class="row">
<div class="col-md-12 form-group"><textarea cols="45" rows="6" placeholder="Message" class="form-control" name="comments_co" required/></textarea></div>
</div>
<div class="row">
<div class="col-md-12 form-group"><?php
$a_con=rand(0,9);
$b_con=rand(0,9);
?>
Human Test <?php echo $a_con." + ".$b_con?> =
</div>
</div>
<div class="row">
<div class="col-md-12 form-group"><input type="text" value="" placeholder="Human Test" class="form-control" name="value_num" required/>
<input class="input" name="captcha_num_hidden_contact" id="captcha_num_hidden_contact" type="hidden" value="<?php echo $a_con+$b_con;?>"/>
</div>
</div>
<div class="row">
<div class="col-md-12 form-group"><input type="submit" name="submit" class="btn btn-submit" /></div>
</div>
</form>
And here is
contact_mail.php
<?php
$errors = array(); // array to hold validation errors
$data = array(); // array to pass back data
//error_reporting(0);
// validate the variables ======================================================
// if any of these variables don't exist, add an error to our $errors array
if (isset($_POST['submit'])){
if (empty($_POST['name_co']))
$errors['name_co'] = 'Name is required.';
if (empty($_POST['email_co']))
$errors['email_co'] = 'Email is required.';
if (empty($_POST['mobile'])){
$errors['mobile'] = 'Mobile no is required.';
} else if(strlen((string)$_POST['mobile']) < 10){
$errors['mobile'] = 'Please enter a valid Mobil No.';
}
if (empty($_POST['comments_co']))
$errors['comments_co'] = 'Comments is required.';
if (empty($_POST['value_num'])) {
$errors['value_num'] = 'Human Test is required.';
}
else if ($_POST['captcha_num_hidden_contact'] != $_POST['value_num']) {
$errors['captcha_num_hidden_contact'] = 'Please enter the correct result.';
}
}
// return a response ===========================================================
// if there are any errors in our errors array, return a success boolean of false
if (!empty($errors)) {
// if there are items in our errors array, return those errors
$data['success'] = false;
$data['errors'] = $errors;
} else {
// if there are no errors process our form, then return a message
// DO ALL YOUR FORM PROCESSING HERE
// THIS CAN BE WHATEVER YOU WANT TO DO (LOGIN, SAVE, UPDATE, WHATEVER)
$email_subject = 'Query From Contact Us';
// $message = '<div><strong>Query From Contact Us : </strong></div>';
// $message .= '<div>---------------------------------------- </div>';
// $message .= '<div><strong>Name: </strong>' . $_POST['name_co'] . '</div>';
// $message .= '<div><strong>Email: </strong>' . $_POST['email_co'] . '</div>';
// $message .= '<div><strong>Service: </strong>' . $_POST['option_type'] . '</div>';
// $message .= '<div><strong>Subject: </strong>' . $_POST['subject_co'] . '</div>';
// $message .= '<div><strong>Mobile: </strong>' . $_POST['mobile'] . '</div>';
// $message .= '<div><strong>Comments: </strong>' . $_POST['comments_co'] . '</div>';
$email_subject1 = 'Acknowledgement';
$headers1 = "MIME-Version: 1.0\r\n";
$headers1 .= "Content-type: text/html; charset=iso-8859-1" . "\r\n";
$headers1 .= "From: "."\r\n";
$mailstatus1 = mail($_POST['email_co'], $email_subject1, $message1, $headers1, "");
// show a message of success and provide a true success variable
$data['success'] = true;
$data['message'] = 'Your Query has been successfully submit. We will contact you very soon!!';
header("location:thank-you.php");
exit;
}
//echo json_encode($data);
// return all our data to an AJAX call
My main problem is that I want to print the error message on the form page but I was unable to print it.

Answer 1

As mentioned in comments I implemented your code on one page.
changed your
<form action="contact_mail.php" method="post" name="contact_Form" id="contactform">
into
<form target="_self" method="post" name="contact_Form" id="contactform" enctype="multipart/form-data">
and added printing errors as in #Bernhard Answer
echo implode('<br>', $data['errors']);
Also changed pattern in this line
<div class="col-md-6 form-group"><input type="text" value="" placeholder="Phone Number" class="form-control" name="mobile" pattern="[123456789]{9}" required /></div>
I am just going to say that when you will be ready consider user input validation in php not just html and using library for sending email such as PHPMailer.
Here is whole code
<?php
$errors = array(); // array to hold validation errors
$data = array(); // array to pass back data
//error_reporting(0);
// validate the variables ======================================================
// if any of these variables don't exist, add an error to our $errors array
if (isset($_POST['submit'])){
if (empty($_POST['name_co']))
$errors['name_co'] = 'Name is required.';
if (empty($_POST['email_co']))
$errors['email_co'] = 'Email is required.';
if (empty($_POST['mobile'])){
$errors['mobile'] = 'Mobile no is required.';
} else if(strlen((string)$_POST['mobile']) < 10){
$errors['mobile'] = 'Please enter a valid Mobil No.';
}
if (empty($_POST['comments_co']))
$errors['comments_co'] = 'Comments is required.';
if (empty($_POST['value_num'])) {
$errors['value_num'] = 'Human Test is required.';
}
else if ($_POST['captcha_num_hidden_contact'] != $_POST['value_num']) {
$errors['captcha_num_hidden_contact'] = 'Please enter the correct result.';
}
}
// return a response ===========================================================
// if there are any errors in our errors array, return a success boolean of false
if (!empty($errors)) {
// if there are items in our errors array, return those errors
$data['success'] = false;
$data['errors'] = $errors;
echo implode('<br>', $data['errors']);
} else {
// if there are no errors process our form, then return a message
// DO ALL YOUR FORM PROCESSING HERE
// THIS CAN BE WHATEVER YOU WANT TO DO (LOGIN, SAVE, UPDATE, WHATEVER)
$email_subject = 'Query From Contact Us';
// $message = '<div><strong>Query From Contact Us : </strong></div>';
// $message .= '<div>---------------------------------------- </div>';
// $message .= '<div><strong>Name: </strong>' . $_POST['name_co'] . '</div>';
// $message .= '<div><strong>Email: </strong>' . $_POST['email_co'] . '</div>';
// $message .= '<div><strong>Service: </strong>' . $_POST['option_type'] . '</div>';
// $message .= '<div><strong>Subject: </strong>' . $_POST['subject_co'] . '</div>';
// $message .= '<div><strong>Mobile: </strong>' . $_POST['mobile'] . '</div>';
// $message .= '<div><strong>Comments: </strong>' . $_POST['comments_co'] . '</div>';
$email_subject1 = 'Acknowledgement';
$headers1 = "MIME-Version: 1.0\r\n";
$headers1 .= "Content-type: text/html; charset=iso-8859-1" . "\r\n";
$headers1 .= "From: "."\r\n";
$mailstatus1 = mail($_POST['email_co'], $email_subject1, $message1, $headers1, "");
// show a message of success and provide a true success variable
$data['success'] = true;
$data['message'] = 'Your Query has been successfully submit. We will contact you very soon!!';
//header("location:thank-you.php");
}
?>
<form target="_self" method="post" name="contact_Form" id="contactform" enctype="multipart/form-data">
<div class="row">
<div class="col-md-12 page_subtitle">Get in Touch</div>
</div>
<div class="row mt-30">
<div class="col-md-12 form-group"><input type="text" value="<?php if (isset($errors['name_co'])): echo $errors; endif; ?>" placeholder="Name" class="form-control" name="name_co" ></div>
</div>
<div class="row">
<div class="col-md-6 form-group"><input type="text" id="txtEmail" value="" placeholder="Email ID" class="form-control" name="email_co" pattern="[a-z0-9._%+-]+#[a-z0-9.-]+\.[a-z]{2,63}$" required /></div>
<div class="col-md-6 form-group"><input type="text" value="" placeholder="Phone Number" class="form-control" name="mobile" pattern="[123456789]{9}" required /></div>
</div>
<div class="row">
<div class="col-md-12 form-group"><textarea cols="45" rows="6" placeholder="Message" class="form-control" name="comments_co" required/></textarea></div>
</div>
<div class="row">
<div class="col-md-12 form-group"><?php
$a_con=rand(0,9);
$b_con=rand(0,9);
?>
Human Test <?php echo $a_con." + ".$b_con?> =
</div>
</div>
<div class="row">
<div class="col-md-12 form-group"><input type="text" value="" placeholder="Human Test" class="form-control" name="value_num" required/>
<input class="input" name="captcha_num_hidden_contact" id="captcha_num_hidden_contact" type="hidden" value="<?php echo $a_con+$b_con;?>"/>
</div>
</div>
<div class="row">
<div class="col-md-12 form-group"><input type="submit" name="submit" class="btn btn-submit" /></div>
</div>
</form>

Answer 2

The solution is simple. You only need to output the Array with the errors below
if (!empty($errors)) {
You can do this like so:
echo implode('<br>', $data['errors']);
implode() will put the array together to a string. is put between each array-element when it is imploded.