document.getElementById(str).style.display="none";
<html>
<head>
<title></title>
<script language="javascript">
function ondelete(str)
{
document.getElementById(str).style.display="none";
}
</script>
</head>
<body>
<div id="cid_1_info">第一條留言
<a onClick="ondelete('cid_1_info')">刪除</a>></div>
<div id="cid_2_info">第二條留言<a onClick="ondelete('cid_2_info')">刪除</a>></div>
<div id="cid_3_info">第三條留言<a onClick="ondelete('cid_3_info')">刪除</a>></div>
<div id="cid_4_info">第四條留言<a onClick="ondelete('cid_4_info')">刪除</a>></div>
<div id="cid_5_info">第五條留言<a onClick="ondelete('cid_5_info')">刪除</a>></div>
<div id="cid_6_info">第六留言<a onClick="ondelete('cid_6_info')">刪除</a>></div>
<div id="cid_7_info">第七條留言<a onClick="ondelete('cid_7_info')">刪除</a>></div>
<div id="cid_8_info">第八條留言<a onClick="ondelete('cid_8_info')">刪除</a>></div>
</html>
