All passwords are found hidden in the page source or a link to them hidden in the page source.(that i have seen anyways.)
The code for the first password is this
<script language=JavaScript>
{
var a="null";
function check()
{
if (document.a.c.value == a)
{
document.location.href="http://www.hackertest.net/"+document.a.c.value+".htm";
}
else
{
alert ("Try again");
}
}
}
</script>