DIV节点问题parentnode

<html>
<head>
<script  language="javascript">
function myDelete()
{
var oTable = document.getElementById("memeber");
//删除该行
this.parentNode.parentNode.parentNode.removeChild(this.parentNode.parentNode);
}
window.onload=function(){
var oTable = document.getElementById("memeber");
var oTd;
//动态添加delete链接
for(var i=1;i<oTable.rows.length;i++)
{
oTd = oTable.rows[i].insertCell(5);
oTd.innerHTML = "<a href='#'>delete</a>";
oTd.firstChild.onclick = myDelete; //添加删除事件
}
}
</script>
<style>
.datalist{
border:1px solid #963; /*表格边框*/
font-family:Arial, Helvetica, sans-serif;/*表格字体*/
border-collapse: collapse;/*边框重叠*/
background-color:#09F;
font-size:14px;
}
.datalist caption{
padding-bottom:4px;
font:bold 1.4em;
text-align:left;
}
.datalist th{
border:1px solid #09F;
background-color:#9F3;
color:#FFF;
font-weight:bold;
padding-top:4px; padding-bottom:4px;
padding-left:12px;
padding-right:12px;
text-align:center;
}
.datalist td{
border:1px solid #09F; /*单元格边框*/
text-align:left;
padding-top:4px; padding-bottom: 4px;
padding-left:10px; padding-right:10px;
}
.datalist tr:hover ,.datalist tr.altrow{  /*动态变色，在火狐中有效，IE中加javascript*/
background-color:#9C0;}
.datalist td a:link,.datalink td a:visted{
color:#09F;
text-decoration:underline;
}
.datalist td a:hover{
color:#000;
text-decoration:none;
}
</style>
</head>
<body>
<table class="datalist" summary="list of members in EE Studay" id="memeber">
<caption>Member List</caption>
<tr>
<th scope="col">Name</th>
<th scope="col">Class</th>
<th scope="col">Birthday</th>
<th scope="col">Constellation</th>
<th scope="col">Mobile</th>
</tr>
<tr>
<td>isaac</td>
<td>W13</td>
<td>Jun 24th</td>
<td>Cancer</td>
<td>1118159</td>
</tr>
<tr>
<td>girlwing</td>
<td>W210</td>
<td>Sep 16th</td>
<td>Virgo</td>
<td>1307994</td>
</tr>
<tr>
<td>tastestory</td>
<td>W15</td>
<td>Nov 29th</td>
<td>Sagittarius</td>
<td>1095245</td>
</tr>
<tr>
<td>lovehate</td>
<td>W47</td>
<td>Sep 5th</td>
<td>Virgo</td>
<td>6098017</td>
</tr>
<tr>
<td>slepox</td>
<td>W19</td>
<td>Nov 18th</td>
<td>Scorpio</td>
<td>0658635</td>
</tr>
<tr>
<td>smartlau</td>
<td>W19</td>
<td>Dec 30th</td>
<td>Capricorn</td>
<td>0006621</td>
</tr>
<tr>
<td>whaler</td>
<td>W19</td>
<td>Jan 18th</td>
<td>Capricorn</td>
<td>1851918</td>
</tr>
<tr>
<td>shenhuanyan</td>
<td>W25</td>
<td>Jan 31th</td>
<td>Aquarius</td>
<td>0621827</td>
</tr>
<tr>
<td>tuonene</td>
<td>W210</td>
<td>Nov 26th</td>
<td>Sagittarius</td>
<td>0091704</td>
</tr>
<tr>
<td>ArthurRivers</td>
<td>W91</td>
<td>Feb 26th</td>
<td>Pisces</td>
<td>0468357</td>
</tr>
<tr>
<td>reconzansp</td>
<td>W09</td>
<td>Oct 13th</td>
<td>Libra</td>
<td>3643041</td>
</tr>
<tr>
<td>linear</td>
<td>W86</td>
<td>Aug 18th</td>
<td>Leo</td>
<td>6398341</td>
</tr>
<tr>
<td>laopiao</td>
<td>W41</td>
<td>May 17th</td>
<td>Taurus</td>
<td>1254004</td>
</tr>
<tr>
<td>dovecho</td>
<td>W19</td>
<td>Dec 9th</td>
<td>Sagittarius</td>
<td>1892013</td>
</tr>
<tr>
<td>shanghen</td>
<td>W42</td>
<td>May 24th</td>
<td>Gemini</td>
<td>1544254</td>
</tr>
<tr>
<td>venessawj</td>
<td>W45</td>
<td>Apr 1st</td>
<td>Aries</td>
<td>1523753</td>
</tr>
<tr>
<td>lightyear</td>
<td>W311</td>
<td>Mar 23th</td>
<td>Aries</td>
<td>1002908</td>
</tr>
</table>
</body>
</html>
-----------------------------------------------------------
很简单的问题，这段代码是对的
this.parentNode.parentNode.parentNode.removeChild(this.parentNode.parentNode);
这段代码是什么意思，请说出他们分别引用顺序