求教如何合并表格

Question

<table border=1 id=t1>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
</table>
<P>
<table border=1 id=t2>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
    <tr><td>aaa</td><td>aaa</td><td>aaa</td><td>aaa</td></tr>
</table>
<script>
function fun1(){
    var oTable = document.getElementById("t1");
    var oTrList = oTable.rows;
    oTrList[0].cells[0].colSpan = 2;
    oTrList[0].cells[1].removeNode();
}
fun1()function fun2(){
    var oTable = document.getElementById("t2");
    var oTrList = oTable.rows;
    oTrList[0].cells[0].rowSpan = 2;
    oTrList[1].cells[0].removeNode();
}
fun2()
</script>IE ONLY....