Complex Login JavaScript

<script type = "text/javascript">

// Note: Like all Javascript password scripts, this is hopelessly insecure as the user can see
//the valid usernames/passwords and the redirect url simply with View Source.
// And the user can obtain another three tries simply by refreshing the page.
//So do not use for anything serious!

var count = 2;
function validate() {
var un = document.myform.username.value;
var pw = document.myform.pword.value;
var valid = false;



var unArray = ["Philip", "George", "Sarah", "Michael"];  // as many as you like - no comma after final entry
var pwArray = ["Password1", "Password2", "Password3", "Password4"];  // the corresponding passwords;

for (var i=0; i <unArray.length; i++) {
if ((un == unArray[i]) && (pw == pwArray[i])) {
valid = true;
break;
}
}

if (valid) {
alert ("Login was successful");
window.location = "http://www.google.com";
return false;
}

var t = " tries";
if (count == 1) {t = " try"}

if (count >= 1) {
alert ("Invalid username and/or password.  You have " + count + t + " left.");
document.myform.username.value = "";
document.myform.pword.value = "";
setTimeout("document.myform.username.focus()", 25);
setTimeout("document.myform.username.select()", 25);
count --;
}

else {
alert ("Still incorrect! You have no more tries left!");
document.myform.username.value = "No more tries allowed!";
document.myform.pword.value = "";
document.myform.username.disabled = true;
document.myform.pword.disabled = true;
return false;
}

}

</script>

<form name = "myform">
<p>ENTER USER NAME <input type="text" name="username"> ENTER PASSWORD <input type="password" name="pword">
<input type="button" value="Check In" name="Submit" onclick= "validate()">
</p>

</form>