Php 4

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>Add to Bookstore</title>
  <link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<div id="navi"><center><a href="index.html" class="navlink"> Bookstore Home</a> ||
<a href="bookstore.html" class="navlink">Add Book to Store</a> ||
<a href="report.php" class="navlink">List Books</a> ||
<a href="deletebook.html" class="navlink">Delete Book from Store</a></div><center>
<div class="overlay">
<div class="innerbox" id="box">
  <h2>Add to Bookstore</h2>

<?php
// php variable assignments to names used in HTML file
  $title = $_POST['title'];
  $last_name = $_POST['alastname'];
  $first_name = $_POST['afirstname'];
  $format = $_POST['format'];
  $price = $_POST['price'];
  $isbn = $_POST['isbn'];

  // check inputs
  if ( empty($title) ) {
	  echo "You must enter a book title. <br />";
  }

	if (strlen($isbn)!=10) {
	echo "ISBN-10 must be 10 Characters/Numbers long. <br />";
	  // ISBN codes also include letters occasionally so this should not be made numeric.
	}


  //run only if title is includes and ISBN is 10 numbers/letters long
  if ( !empty($title) && strlen($isbn==10) ) {
  // connect to database using login info, and database name
  $dbc = mysqli_connect('localhost', 'root', '', 'bookstore_kariann')
	or die('Error connecting to MySQL server.'); // terminates code if failed


  // creates the SQL query and stores as string in a PHP variable
  $query = "INSERT INTO books (title, author_last, author_first, format, price, isbncode) " .
  "VALUES ('$title', '$last_name', '$first_name', '$format', '$price', '$isbn')";


	  	/* testing echoes
echo $query;
echo '<br />'; */


  // isses the query using the msqli_query function that allows it to add data to the database table
  $result = mysqli_query($dbc, $query)
    or die('Error querying database.'); // terminates if failed

	mysqli_close($dbc); // close connection

  // output for data submitted
  echo '<h3>Book has been entered into database.</h3><br />';
  echo 'Title: ' . $title . '<br />';
  echo 'Author Last Name: ' . $last_name . '<br />';
  echo 'Author First Name: ' . $first_name . '<br />';
  echo 'Format: ' . $format . '<br />';
  echo 'Price: ' . $price . '<br />';
  echo 'ISBN-10: ' . $isbn . '<br />'; }
?>
</div></div></center>
</body>
</html>