看看你的,名字是否都对!!应该没有问题的!:
<form>
<select name=bbb>
<option value="1">1
<option value="2">2
<option value="3">3
</select>
<a onclick="alert(bbb.options[2].value)" href="#">form.bbb.options[2].value</a>
</form>
<form>
<select name=bbb>
<option value="1">1
<option value="2">2
<option value="3">3
</select>
<a onclick="alert(bbb.options[2].value)" href="#">form.bbb.options[2].value</a>
</form>
<select name=aaa>
<option value="a1">a1
<option value="a2">a2
<option value="a3">a3
</select>
<a onclick="alert(aaa.options[2].value)" href="#">form.aaa.options[2].value</a><br>
<select name=bbb>
<option value="b1">b1
<option value="b2">b2
<option value="b3">b3
</select>
<a onclick="alert(bbb.options[2].value)" href="#">form.bbb.options[2].value</a><br>
<select name=ccc>
<option value="c1">c1
<option value="b2">c2
<option value="c3">c3
</select>
<a onclick="alert(ccc.options[2].value)" href="#">form.ccc.options[2].value</a>
</form>