<form method="POST" ><select size="1" name="slttest" >
<option value="aaa">aaa</option>
<option value="bbb">bbb</option>
<option value="ccc">ccc</option>
</select><input type="button" value="变灰" name="B1" onclick="document.all.slttest.disabled=true;"></p>
</form>
<option value="aaa">aaa</option>
<option value="bbb">bbb</option>
<option value="ccc">ccc</option>
</select><input type="button" value="变灰" name="B1" onclick="document.all.slttest.disabled=true;"></p>
</form>
<option>asdf</option>
</select>
<option value="1">aaa</option>
<option value="2">bbb</option>
</sclect>
你还可以直接点击这个复选框看其变的切换
<input type=checkbox checked onclick="document.all.list.disabled=this.checked">