<script language="javascript">
<!--//
/*This Script allows people to enter by using a form that asks for a
UserID and Password*/
function pasuser(form) {
if (form.id.value=="JavaScript") {
if (form.pass.value=="Kit") {
location="page2.html"
} else {
alert("Invalid Password")
}
} else { alert("Invalid UserID")
}
}
//-->
</script>
<center>
<table bgcolor="white" cellpadding="12" border="1">
<tr><td colspan="2"><center><h1><i><b>Login
Area</b></i></h1></center></td></tr>
<tr><td><h1><i><b>UserID:</b></i></h1></td><td><form name="login"><input
name="id" type="text"></td></tr>
<tr><td><h1><i><b>Password:</b></i></h1></td><td><input name="pass"
type="password"></td></tr>
<tr><td><center><input type="button" value="Login"
onClick="pasuser(this.form)"></center></td><td><center><br><input
type="Reset"></form></td></tr></table></center>
All you have to do to bypass this script is View Source - a more efficient method (still very basic), using PHP where they cannot bypass it as easily would be to use:
Code:
<?php
$userpass = $_POST['pass'];
if($userpass == "password") {
echo "Thank you for using this script.";
} else {
echo "That password was incorrect.";
}
?>
i once used something similar to this 
