Untitled

<!doctype html>
<html>
<head>
<title>User Registration</title>
</head>
<body>
<h1>User Registration</h1>
<form action="" method="post">
<label>firstname :</label><input type="text" name="firstname"  required pattern="^[A-Za-z]+"><br/><br/>
<label>lastname:</label><input type="text" name="lastname" required pattern="^[A-Za-z]+"><br/><br/>
<label>user :</label><input type="text" name="user" required pattern="^[A-Za-z0-9]+" ><br/><br/>
<label>password :</label><input type="password" name="password" required pattern="^[A-Za-z0-9]+"><br/><br/>
<label>dob :</label><input type="date" name="dob" required ="" ><br/><br/>
<label>gender :</label><input type="text" name="gender" required pattern="^[A-Za-z]+"><br/><br/>
<label>emailid :</label><input type="text" name="emailid" required ="^[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}$/"><br/><br/>
<label>collegename :</label><input type="text" name="collegename" required pattern="^[A-Za-z]+"><br/><br/>
<label>areaname :</label><input type="text" name="areaname" required pattern="^[A-Za-z]+"><br/><br/>
<label>phonenumber :</label><input type="text" name="phonenumber" required pattern="^[0-9]+"><br/><br/>


<input type="submit" value="Register" name="submit"><br/><br/>
<!-- Login Link -->
<a href="login.php">Login</a>
</form>
<?php
if(isset($_POST["submit"])){

 $firstname = $_POST['firstname'];
 $lastname = $_POST['lastname'];
 $user = $_POST['user'];
 $password = $_POST['password'];
 $dob = $_POST['dob'];
 $gender = $_POST['gender'];
 $emailid = $_POST['emailid'];
 $collegename = $_POST['collegename'];
 $areaname = $_POST['areaname'];
 $phonenumber = $_POST['phonenumber'];
 $conn = new mysqli('localhost', 'root', 'mannat123') or die (mysqli_error()); // DB Connection
 $db = mysqli_select_db($conn, 'sellmybook') or die("DB Error"); // Select DB from database
 //Selecting Database
 $query = mysqli_query($conn, "SELECT * FROM signup_details WHERE user='".$user."'");
 $numrows = mysqli_num_rows($query);
 if($numrows == 0)
 {
 //Insert to Mysqli Query
 $sql = "INSERT INTO signup_details(firstname,lastname,user,password,dob,gender,emailid,collegename,areaname,phonenumber) VALUES('$firstname','$lastname','$user','$password','$dob','$gender','$emailid','$collegename','$areaname','$phonenumber')";
 $result = mysqli_query($conn, $sql);
 //Result Message
 if($result){
 echo "Your Account Created Successfully";
 }
 else
 {
 echo "Failure!";
 }
 }
 else
 {
 echo "That Username already exists! Please try again.";
 }

}
?>
</body>
</html>