giúp đỡ javascript

đây là 1 câu đố trên trang xi-tin.net .Mình cố gắng mà ko giải đáp được giúp mình với.mình điền mật mã là 2010 mà bị báo sai password.

<center><font size="6">CHAP I<br>LEVEL 2<br><b>NINJA SCRIPT</b></font></center><br><br>
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<script>
function a()
{
var a="20l0";
if(form.a.value==a){alert("Good - Chuc Mung Ban Da Hoan Thanh Duoc Lv2 !!!");x++;nextlevel();}else{alert("pass sai - Try Again");}
}
</script>

<form action="javascript:a()" name="form">
Nhap pass vao day(Enter Pass):<input name="a" id="a" type="text">
<input value="login" type="submit">
</form>
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<div id="next"></div><a href="http://xi-tin.net"></a>
<script>var x=0;function nextlevel(){if(x>0){document.getElementById("next" ).innerHTML = "<form name='nextlv' method=POST action='3.php'><input type=hidden name='level' value=3><input type=hidden name='name' value="+name0+"><input type=hidden name='nickname' value="+nickname0+"><input type=hidden name='location' value="+location0+"></form>";document.nextlv.submit();}else alert("a");}</script>
<br><br><br><br><br><br><br><br><br><br><br><br><b r><br><br><center><a href="http://xi-tin.net">Hay thu kiem tra kien thuc ve javascript cua ban.Bang cach vuot qua cac thu thach hacking Javascript tai day<br>test,hack,hacking,javascript,Music,nhac,Phi m,Game,Comic,truyen tranh,forum,Dien dan,Blog,Hosting,shoping,software,giai tri,online,vuong quoc gau,xitin</a></center>
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