<form action='' method='post'>
<input type='password' name='pass'><br />
<input type='submit' name='submit' value="Go">
</form>
<?php
if(isset($_POST['submit'])){
$parola=1234; //tuk si pi6e6 adminskata parola
$pass=htmlspecialchars($_POST['pass']);
$pass=addslashes($pass);
if($parola==$pass){ //proverqvame dali vyvedenata parola e vqrna
echo "OK"; //tuk si pi6e6 koda,koito da se pokazva ako pasa e veren
}else{ //tuk ako pasa ne e veren
echo '<script>
alert("Typak,pasa ne e veren..")
</script>';
}}
?>