<form role="form" method="GET">
<select name="category">
<option value="judul">Judul buku</option>
<option value="pengarang">Pengarang</option>
<option value="penerbit">Penerbit</option>
<option value="subyek">Kategori</option>
<option value="thn_terbit">Tahun terbit</option>
<option value="no_rak">No Rak</option>
<option value="isbn">ISBN</option>
</select>
<input type="text" placeholder="Masukkan kata kunci" name="keyword">
<input type="submit" name="search" value="cari" class="btn btn-info">
</form>