单选按钮的onclick事件

<form name="form1" method="post" action="">
  <input name="radiobutton" type="radio" value="0" checked

onclick="form1.select1.style.display='';form1.select2.style.display='none';">
  11
  <input type="radio" name="radiobutton" value="1"

onclick="form1.select2.style.display='';form1.select1.style.display='none';">
  22 
  <select name="select1" style="display:yes">
    <option value="0" selected>11111</option>
    <option value="1">2222</option>
  </select>
  <select name="select2" style="display:none">
    <option value="3" selected>33333</option>
    <option value="4">44444</option>
  </select>
</form>