JQuery操作一个表格

<!----><script type="text/javascript" src="http://www.cnblogs.com/Files/liydotnet/jquery-1.2.3.js"></script>
<style type="text/css">
.mainTable{ background-color:#ffcc00; width:85%; margin:auto; font-size:12px}
.mainTable td{ height:22px}
.line{ background-color:#fffff7; height:25px}
.line-none{ background-color:#fffff7; height:25px}
.selected{ background-color:#fff5fa}
.template{ background-color:#ffffdd;display:none; color:#e8f5fe}
.mainTable a{ margin-right:6px}
.mainTable a:link{color:#92b0dd }
.mainTable a:visited{color:#92b0dd}
.mainTable a:hover{color:#FF0000}
</style>
<table class="mainTable" cellspacing="1" cellpadding="1">
<tbody>
<tr class="template">
<td style="padding-left: 5px" colspan="3"></td>
</tr>
<tr class="line">
<td style="padding-left: 6px"></td>
<td></td>
<td style="width: 30%" align="center"><a onclick="javascript:do_select(this)" href="javascript:;">选择</a> <a onclick="javascript:do_add(this)" href="javascript:;">增加一行↑</a> <a onclick="javascript:do_copy(this)" href="javascript:;">复制此行↓</a> <a onclick="javascript:do_delete(this)" href="javascript:;">删除</a> </td>
</tr>
</tbody>
</table>
<script type="text/javascript">
function do_select(aa)
{
var id=$(aa);
id.parents("tr").addClass("selected");
id.attr("onclick","javascript:do_reset(this)").html("取消")
}
function do_reset(aa)
{
var id=$(aa);
id.parents("tr").removeClass("selected");
id.attr("onclick","javascript:do_select(this)").html("选择")
}
function do_copy(aa)
{
var id=$(aa);
var copy=id.parents("tr").clone();
var first=copy.find("td:first");
first.html("》"+first.html())
id.parents("tr").after(copy);
}
function do_add(aa)
{
var id=$(aa);
var template=$(".template").clone().attr("class","line-none");
var add=$(".line-none");
id.parents("tr").prev(".line-none").remove();
template.show().find("td:eq(0)").html("我是根据模板复制的的");
id.parents("tr").before(template);
}
function do_delete(aa)
{
var id=$(aa);
id.parents("tr").remove();
}
</script>