PHP Code Not Entering Data Into Database

Question

I'm having trouble sending my forms to my database. I've tried for an hour to fix the issue; I riddled my code with "echo mysqli_error();" but received no error, simply a lack of the new data into my database (it seems as if the submit form isn't reloading the page to send the info either). The database works for the rest of my pages using config.php, connectDB.php and header.php, so the problem isn't in the database setup. I believe that the error is within the "isset($_POST['submit'])", since it doesn't reload the page with the header(), but I'm providing the rest of my code just in case. (I know this code isn't protected against SQL Injection, form validation is the next step after I fix this):

<?php
require_once ("Includes/config.php"); 
require_once  ("Includes/connectDB.php");
include("Includes/header.php");
if (isset($_POST['submit'])){
                $name = $_POST['name'];
                $email = $_POST['email'];
                $content = $_POST['content'];
                $query = "INSERT INTO requests (name, email, content) VALUES (?, ?, ?)";

                $statement = $databaseConnection->prepare($query);
                $statement->bind_param('sss', $name, $email, $content);
                header('Location: /index.php');

                $statement->execute()
                $statement->store_result();
                setcookie("nameErr"," ", time()+3600);
                setcookie("emailErr"," ", time()+3600);
                setcookie("contentErr"," ", time()+3600);
                setcookie("contentSucc","Announcement Request Successful", time()+3600);
                header('Location: /request.php');

}
?>
<div id="main">
        <ol>
            <li>
                <label for="name">Name:</label> 
                <input type="text" name="name" value="" id="name" />
                <span class="error">* <?php if (isset($_COOKIE["nameErr"])){echo $_COOKIE["nameErr"];}?></span>
            </li>
            <li>
                <label for="email">Email:</label>
                <input type="text" name="email" value="" id="email" style = "position: relative; left: 3px;"/>
                <span class="error" style = "position: relative; left: 3px;">* <?php if (isset($_COOKIE["emailErr"])){echo $_COOKIE["emailErr"];}?></span>
            </li>
            <li>
                    <label for="content">Requested Announcement:</label><br>
                    <textarea rows="18" cols="140" name="content" id="content"></textarea>
                    <br>
                    <span class="error"> <?php if (isset($_COOKIE["contentErr"])){echo $_COOKIE["contentErr"];}?></span>
                    <span class="error"> <?php if (isset($_COOKIE["contentSucc"])){echo $_COOKIE["contentSucc"];}?></span>
            </li>
        </ol>
        <input type="submit" name="submit" value="Submit " style = "position: relative; left: 40px;" /> 
        <!-- onclick="window.location='request.php';" -->   
        <p>
            <a class="cancel" href="index.php" style = "position: relative; left: 40px;">Cancel</a>
        </p>
</div>

Answer 1

1. Your redirecting to another webpage before the SQL is executed.
2. You don't have a semicolon at the end of the line.
3. You don't have a <form> around the <input> tags.
4. You shouldn't have to do very much else to stop SQL injection. As long as your using MySQLi properly, your fine.

Change this

            $statement->bind_param('sss', $name, $email, $content);
            header('Location: /index.php');

            $statement->execute()

to this

            $statement->bind_param('sss', $name, $email, $content);
            $statement->execute();
            $statement->close();

            header('Location: /index.php');