Disappearing button

[Eko Priono]

Why the following buttons misteriously vanished when browsed with
Arachne?

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<form>
  <div align="center"><center><p>
  <input onclick="location='daftarkan.html'" type="button" value="SETUJU">
  <input onclick="location='/'" type="button" value="TIDAK SETUJU">
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URL: http://www.plasa.com/freemail/daftar.html

--Eko