user system

PHP kode 

 <? 
 //put denne kode for at tjekke login
 session_start();
 if(!session_is_registered(myusername)){
 header("location:index.php");
 }
 ?>

PHP kode 

 <?php
 $host="localhost"; // Host name 
 $username="xxxx"; // Mysql username 
 $password="xxxx"; // Mysql password 
 $db_name="xxxx"; // Database name 
 $tbl_name="xxxx"; // Table name
 
 // Connect til server and vælge databse.
 mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
 mysql_select_db("$db_name")or die("cannot select DB");
 
 // username and password sent from form 
 $myusername=$_POST['myusername']; 
 $mypassword=$_POST['mypassword'];
 
 // To protect MySQL injection (more detail about MySQL injection)
 $myusername = stripslashes($myusername);
 $mypassword = stripslashes($mypassword);
 $myusername = mysql_real_escape_string($myusername);
 $mypassword = mysql_real_escape_string($mypassword);
 
 $sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
 $result=mysql_query($sql);
 
 // Mysql_num_row is counting table row
 $count=mysql_num_rows($result);
 // If result matched $myusername and $mypassword, table row must be 1 row
 
 if($count==1){
 // Register $myusername, $mypassword and redirect to file "login_success.php"
 session_register("myusername");
 session_register("mypassword"); 
 header("location:login_success.php");
 }
 else {
 echo "Forkert brugernavn eller Password";
 }
 ?>