I am creating a simple registration form, I have created all files needed to make complete form registration and login. registration should have Firstname, Lastname, username and password, I have tested with two parameters meaning username and password my codes works perfectly but when I add more parameters eg Firstname and Lastname I get error: Fatal error: Cannot use isset() on the result of an expression
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Registration</title>
<link rel="stylesheet" href="css/style.css" />
</head>
<body>
<?php
#include database connection files
require('db.php');
//inserting data to our database
// If form submitted, insert values into the database.
if(!isset($_REQUEST['username'] || $_REQUEST['Firstname'] || $_REQUEST['Lastname'])){
// removes backslashes
$username = stripslashes($_REQUEST['username']);
//escapes special characters in a string
$username = mysqli_real_escape_string($con,$username);
$Firstname = stripslashes($_REQUEST['Firstname']);
$Firstname = mysqli_real_escape_string($con,$Firstname);
$Lastname = stripslashes($_REQUEST['Lastname']);
$Lastname = mysqli_real_escape_string($con,$Lastname);
$email = stripslashes($_REQUEST['email']);
$email = mysqli_real_escape_string($con,$email);
$password = stripslashes($_REQUEST['password']);
$password = mysqli_real_escape_string($con,$password);
$trn_date = date("Y-m-d H:i:s");
$query = "INSERT into `users` (username, Firstname, Lastname, password, email, trn_date)
VALUES ('$username',Firstname,Lastname, '".md5($password)."', '$email', '$trn_date')";
$result = mysqli_query($con,$query);
if($result){
echo "<div class='form'>
<h3>You are registered successfully.</h3>
<br/>Click here to <a href='login.php'>Login</a></div>";
}
}
else{
?>
<div class="form">
<h1>Registration</h1>
<form name="registration" action="" method="post">
<input type="text" name="Firstname" placeholder="Firstname" required/>
<input type="text" name="Lastname" placeholder="Lastname" required/>
<input type="text" name="username" placeholder="Username" required />
<input type="email" name="email" placeholder="Email" required />
<input type="password" name="password" placeholder="Password" required />
<input type="submit" name="submit" value="Register" />
</form>
</div>
<?php } ?>
</body>
</html>
Unfortunately, I can't figure it out , what is wrong with my code?