js Select下拉列表框进行多选、移除、交换内容的具体实现方法

代码如下:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<span class='wp_keywordlink_affiliate'><a href="tag/html" title="查看 html 中的全部文章" target="_blank">html</a></span>4/loose.dtd">
<<span class='wp_keywordlink_affiliate'><a href="tag/html" title="查看 html 中的全部文章" target="_blank">html</a></span>>
<head>
<title>Select下拉列表框进行多选、移除、交换内容</title>
<meta http-equiv="Content-Type" content="text/<span class='wp_keywordlink_affiliate'><a href="tag/html" title="查看 html 中的全部文章" target="_blank">html</a></span>; charset=gb2312">
</head>
<body style="font-size:12px">
<form name="form1" method="post" action="">
<table width="380" border="0" align="center" cellpadding="0" cellspacing="0">
  <tr>
    <td width="150"><table width="150" border="0" cellpadding="1" cellspacing="1" bgcolor="#CAFAFC">
      <tr>
        <td height="25" background="wp-content/uploads/2012/05/79760-772704496-8.gif" bgcolor="#FFFFFF">　　　请选择：</td>
      </tr>
      <tr>
        <td align="center" bgcolor="#FFFFFF"><select name="sel_place1" size="6" multiple id="sel_place1" style="width:100px " >
          <option value="sel1">江苏省</option>
          <option value="sel2">广东省</option>
          <option value="sel3">河南省</option>
          <option value="sel4">吉林省</option>
          <option value="sel5">浙江省</option>
        </select></td>
      </tr>
    </table></td>
    <td width="80" align="center" valign="bottom"><input name="sure1" type="button" id="sure1"
  onClick="allsel(document.form1.sel_place2,document.form1.sel_place1);" value="<<">

<input name="sure2" type="button" id="sure2"
  onClick="allsel(document.form1.sel_place1,document.form1.sel_place2);" value=">>" align="center" height="2"></td>
    <td width="150"><table width="150" border="0" cellpadding="1" cellspacing="1" bgcolor="#CAFAFC">
      <tr>
        <td height="25" background="wp-content/uploads/2012/05/79760-772704496-8.gif" bgcolor="#FFFFFF">　　　请选择：</td>
      </tr>
      <tr>
        <td align="center" bgcolor="#FFFFFF"><select name="sel_place2" size="6" multiple id="sel_place2" style="width:100px ">
            </select></td>
      </tr>
    </table></td>
  </tr>
</table>
</form>
<script language="javascript">
function allsel(n1,n2)
{
  while(n1.selectedIndex!=-1)
  {
   var indx=n1.selectedIndex;
   var t=n1.options[indx].text;
   n2.options.add(new Option(t));
   n1.remove(indx);
  }
}
</script>
</body>
</html></td>
   </tr>
 </table>