js控制div显示与隐藏

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="https://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>js显示隐藏层</title>
<script language="JavaScript" type="text/JavaScript">
<!--
function showdiv(targetid,objN){
      var target=document.getElementById(targetid);
      var clicktext=document.getElementById(objN)
            if (target.style.display=="block"){
                target.style.display="none";
                clicktext.innerText="点击查看详细信息";
            } else {
                target.style.display="block";
                clicktext.innerText='关闭详细信息信息';
            }
}
-->
</script>
<style type="text/css">
<!--
body { font: normal 14px "宋体" }
a { text-decoration: none; }
#showtext { cursor: hand; cursor:pointer;}
#showtext2 { cursor: hand; cursor:pointer;}
#contentid { margin-top: 10px; width:100%; border: 1px solid #CCC; background: #F1F1F1; padding: 15px; }
#contentid2 { margin-top: 10px; width: 470px; border: 1px solid #CCC; background: #F1F1F1; padding: 15px; }
.none { display: none; }
-->
</style>
</head>
<body>
<a id="showtext" onClick="showdiv('contentid','showtext')">点击查看详细信息</a>
<div id="contentid" class="none">打开的内容</div>
<p></p>
<a id="showtext2" onClick="showdiv('contentid2','showtext2')">点击查看详细信息</a>
<div id="contentid2" class="none">1<br />
2.<br />
3.<br />
4.<br />
5.<br />
6. <br />
7.<br />
8. <br />
9.<br />
10.<br />
11.<br />
12. <br />
13.<br />
14. <br />
15.<br />
</div>
</body>
</html>