帮小弟我看看这段代码，有什么有关问题
帮我看看这段代码，有什么问题
点“delCell"按钮为什么只能删除最后那两个单元格？然后剩下的就删不掉了。
------解决思路----------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<input id="delRow" type="button" value="delRow" onclick="delRow();" />
<input id="delCell" type="button" value="delCell" onclick="delCell();" />
<table id="tb" border="1" style="width:200px">
<caption>我是标题</caption>
<tr>
<td>疯狂JAVA</td>
<td>JAVA EE</td>
</tr>
<tr>
<td>AJAX</td>
<td>经典JAVA</td>
</tr>
<tr>
<td>XML</td>
<td>ANDROID</td>
</tr>
</table>
<script type="text/javascript">
var tb=document.getElementById("tb");
var delRow=function()
{
if (tb.rows.length>0)
{
tb.deleteRow(tb.rows.length-1);
}
}
var delCell=function()
{
if (tb.rows.length>0)
{
var lastrow=tb.rows[tb.rows.length-1];
if (lastrow.cells.length>0)
{
lastrow.deleteCell(lastrow.cells.length-1);
}
}
}
</script>
</body>
</html>
点“delCell"按钮为什么只能删除最后那两个单元格？然后剩下的就删不掉了。
------解决思路----------------------
var delCell=function()
{
if (tb.rows.length>0)
{
var lastrow=tb.rows[tb.rows.length-1];
if (lastrow.cells.length>0)
{
lastrow.deleteCell(lastrow.cells.length-1);
}
if (lastrow.cells.length==0)
{
tb.deleteRow(tb.rows.length-1);
}
}
}