JavaScript password protection

This JavaScript prompts the user for a password. If it is correct, the user can view the page, and if it is incorrect, the browser jumps to the previous page.
This JavaScript is not completely secure, and can easily be disabled, so don't use it to protect something that is top secret.

This code should be placed between the HEAD tags of the page:

<SCRIPT LANGUAGE="JavaScript">
<!---------- JavaScript begins...

var password = "password" ;
        // The desired password

var message = "The password to view this page is 'password'";
        // The message to show when the user is prompted for the password

var incmess = "Incorrect password! Access denied!";
        // The message to show if the password is incorrect

var pw = prompt (message,"");

if (pw != password) {
        alert (incmess);
        window.history.back ();
}
// JavaScript ends ---------->
</SCRIPT>