<table id="tbl" border="1">
<tr><td>内容1</td></tr>
<tr><td>内容2</td></tr>
<tr><td>内容3</td></tr>
</table>
<script type="text/javascript">
var $ = function(id){return document.getElementById(id)}
var row = $("tbl").insertRow(-1);
var cell = row.insertCell(-1);
cell.innerHTML = "内容4";
</script>
<tr><td>内容1</td></tr>
<tr><td>内容2</td></tr>
<tr><td>内容3</td></tr>
</table>
<script type="text/javascript">
var $ = function(id){return document.getElementById(id)}
var row = $("tbl").insertRow(-1);
var cell = row.insertCell(-1);
cell.innerHTML = "内容4";
</script>
<tr><td>内容1</td></tr>
<tr><td>内容2</td></tr>
<tr><td>内容3</td></tr>
</table>
<script language=javascript>
var len = document.getElementsByTagName("tr").length;
var newRow = tbl.insertRow();
var newCell = newRow.insertCell();
newCell.innerText = "内容"+(++len)
</script>
var n = 3;
var table = div.getElementsByTagName("table")[0];
var row = table.insertRow(n);
var cell = row.insertCell();另外楼主想要插入字符串,可以用indexOf找"</tr>"n次,不过每次都要重写div.innerHTML