PHP/MYSQL Insert is doing nothing - php

Question

I have a simple form set up in HTML to pass values to PHP and put them in a MYSQL database. I just can't fathom why nothing is happening when I click the submit button. Previously it was saying 'failed' but now nothing. I have checked the values from the form - fine. I've checked the database connection - fine. I've checked the SQL statement - well, I can't see any errors.
This is my main HTML page
<p class="subtitle">Let me know what you think</p>
<form action="db_insert.php">
<input name="username" placeholder="Name">
<br>
<textarea name="comments" placeholder="Please type your comments here"
cols=120 rows=5></textarea>
<br>
<input type="button" name="submit" value="submit">
<br>
<p id="commTitle">Comments</p>
<br>
<p id="comment"></p>
This is the PHP
<?php
include 'db_connection.php';
//create database connection
$conn = OpenCon();
$username = htmlspecialchars($_POST['username']);
$comment = htmlspecialchars($_POST['comment']);
$sql = 'INSERT INTO sitecomments(username, comment) VALUES(:username,:comment)';
$stmt = $conn -> prepare($sql);
$stmt -> bindValue(':username', $username);
$stmt -> bindValue(':comment', $comment);
$q_result = $stmt -> execute();
if($q_result){
echo 'Comment Inserted Successfully';
}
else{
echo 'Failed';
}
db_connection.php looks like this (with credentials removed.
<?php
function OpenCon(){
//pass the database details to variables
$host = "localhost";
$dbuser = "*****";
$dbpass = "*****";
$dbname = "*****";
// combine host and db name in to single variable
$dbhost = "mysql:host=$host;dbname=$dbname";
//create PDO from database information
$dbconn = new PDO($dbhost, $dbuser, $dbpass);
return $dbconn;
}
?>
As I said, I've checked the database connection and all is fine so where on earth am I going wrong? My database has 3 fields but one is autoincremented so I haven't included it in the query. I tried the query in MyPHPAdmin and it passed ok.

Answer 1

The first thing I notice is that the input has name of "comments" rather than the $_POST variable you're accessing called comment:
<textarea name="comments" placeholder="Please type your comments here" cols=120 rows=5></textarea>
$comment = htmlspecialchars($_POST['comment']);
Try changing that and see if it fixes the issue.

Answer 2

It would be helpful to handle errors within your code. In your current example if something goes wrong you will have a hard time finding out where the problem is.
You can try all of the following examples from the PHP Docs on PDO error handling and PDO::errorInfo:
Assert your connection is valid:
try {
$dbh = new PDO($dsn, $user, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_WARNING));
} catch (PDOException $e) {
echo 'Connection failed: ' . $e->getMessage();
exit;
}
Assert your SQL is valid
/* Provoke an error -- bogus SQL syntax */
$stmt = $dbh->prepare('bogus sql');
if (!$stmt) {
echo "\nPDO::errorInfo():\n";
print_r($dbh->errorInfo());
}
As usual the error is a pebcak error, and you need to utilize proper debugging tools to find out where your mistakes are. Good luck!