PHP validation checkbox - php

Question

I've scoured the entire internet trying to find a solution to what I'm missing here (or doing wrong). My form doesn't validate even when the check box is checked. Everything else works fine.
It's that checkbox I can't get to work right.
I've tried many different ideas, but it won't validate even with the "terms" checked (such as this example below).
Here's my HTML:
<div class="form-check">
<input type="checkbox" class="form-check-input" name="terms" id="terms" />
<label class="form-check-label" for="terms"><p>I agree to terms of service.</p></label>
</div>
Here's my entire PHP validation (updated with the comments/answers below):
<?php
if(!$_POST) exit;
// Email address verification.
function isEmail($email) { // lots of email validation stuff in here // }
if (!defined("PHP_EOL")) define("PHP_EOL", "\r\n");
$name = $_POST['name'];
$email = $_POST['email'];
$website = $_POST['website'];
$subject = $_POST['subject'];
$comments = $_POST['comments'];
$terms = $_POST['terms'];
//set an error counter to trigger the `exit`
$error_counter = 0;
if(trim($name) == '') {
echo '<div class="error_message">Attention! You must enter your name</div>';
$error_counter++;
}
if(trim($email) == '') {
echo '<div class="error_message">Attention! Please enter a valid email
address.</div>';
$error_counter++;
}
if(!isEmail($email)) {
echo '<div class="error_message">Attention! You have entered an invalid e-
mail address, try again.</div>';
$error_counter++;
}
if(trim($subject) == '') {
echo '<div class="error_message">Attention! Please enter a subject.</div>';
$error_counter++;
}
if(trim($comments) == '') {
echo '<div class="error_message">Attention! Please enter your message.
</div>';
$error_counter++;
}
if(empty($terms)) {
echo '<div class="error_message">Attention! Please agree to our terms of
service.</div>';
$error_counter++;
}
//if `$error_counter > 0 > 0` it will trigger the `exit()` to stop the script and display the errors.
if($error_counter > 0){
exit();
}
if(get_magic_quotes_gpc()) {
$comments = stripslashes($comments);
}
// Configuration option.
// Enter the email address that you want to emails to be sent to.
// Example $address = "joe.doe#yourdomain.com";
$address = "cousinjack#mydomain.com";
// Configuration option.
// i.e. The standard subject will appear as, "You've been contacted by John Doe."
// Example, $e_subject = '$name . ' has contacted you via Your Website.';
$e_subject = 'You have been contacted by ' . $name . '.';
// Configuration option.
// You can change this if you feel that you need to.
// Developers, you may wish to add more fields to the form, in which case you must be sure to add them here.
$e_body = "You have been contacted by $name with regards to $subject, their additional message is as follows." . PHP_EOL . PHP_EOL;
$e_content = "\"$comments\"" . PHP_EOL . PHP_EOL;
$e_reply = "You can contact $name via email, $email ";
$msg = wordwrap( $e_body . $e_content . $e_reply, 70 );
$headers = "From: $email" . PHP_EOL;
$headers .= "Reply-To: $email" . PHP_EOL;
$headers .= "MIME-Version: 1.0" . PHP_EOL;
$headers .= "Content-type: text/plain; charset=utf-8" . PHP_EOL;
$headers .= "Content-Transfer-Encoding: quoted-printable" . PHP_EOL;
if(mail($address, $e_subject, $msg, $headers)) {
// Email has sent successfully, echo a success page.
echo "<fieldset>";
echo "<div id='success_page'>";
echo "<h1>Email Sent Successfully.</h1>";
echo "<p>Thank you <strong>$name</strong>, your message has been submitted to us.</p>";
echo "</div>";
echo "</fieldset>";
} else {
echo 'ERROR!';
}
?>

Answer 1

You don't set any value attribute for your checkbox :
<input type="checkbox" class="form-check-input" name="terms" id="terms" value="yes" />
More informations : https://developer.mozilla.org/fr/docs/Web/HTML/Element/Input/checkbox

Answer 2

I can see your checkbox has no value so the PHP part is getting a garbage/empty value.
In short, just add a required attribute in your HTML side. No need of a check at the server end
<div class="form-check">
<input type="checkbox" class="form-check-input" name="terms" id="terms" required/>
<label class="form-check-label" for="terms"><p>I agree to terms of service.</p></label>
</div>

Answer 3

The problem with your current validation is that you're using if-else wrongly and that you're using exit on every statement which will terminate your script prematurely.
You can do this instead:
For Terms:
<input type="checkbox" class="form-check-input" name="terms" id="terms" value="1"/>
//set an error counter to trigger the `exit`
$error_counter = 0;
if(trim($name) == '') {
echo '<div class="error_message">Attention! You must enter your name</div>';
$error_counter++;
}
if(trim($email) == '') {
echo '<div class="error_message">Attention! Please enter a valid email
address.</div>';
$error_counter++;
}
if(!isEmail($email)) {
echo '<div class="error_message">Attention! You have entered an invalid e-
mail address, try again.</div>';
$error_counter++;
}
if(trim($subject) == '') {
echo '<div class="error_message">Attention! Please enter a subject.</div>';
$error_counter++;
}
if(trim($comments) == '') {
echo '<div class="error_message">Attention! Please enter your message.</div>';
$error_counter++;
}
if(empty($terms)) {
echo '<div class="error_message">Attention! Please agree to our terms of service.</div>';
$error_counter++;
}
//if `$error_counter > 0 > 0` it will trigger the `exit()` to stop the script and display the errors.
if($error_counter > 0){
exit();
}
There's a more beautiful approach to do this. Feel free to add suggestions for the OP.