求一段简单的JS代码

Question

如图所示
类似上图中的级联操作代码，感激不尽！（不要下拉列表关联的）

Answer 1

<TABLE id="tab" border="1">
<TR>
<TD>省/直辖市</TD>
<TD style="cursor:hand" onclick="showcity(this)">北京</TD>
<TD style="cursor:hand" onclick="showcity(this)">天津</TD>
<TD style="cursor:hand" onclick="showcity(this)">宁夏</TD>
</TR>
<TR>
<TD>城市</TD>
</TR>
<TR>
<TD>地区</TD>
</TR>
</TABLE>
<SCRIPT LANGUAGE="JavaScript">
<!--
var prov = 0;
var city = 1;
var dist = 2
var arr = new Array();
arr[0] = ["北京","北京","东城区"];
arr[1] = ["北京","北京","西城区"];
arr[2] = ["北京","北京","崇文区"];
arr[3] = ["北京","北京","宣武区"];
arr[4] = ["天津","天津","河东区"];
arr[5] = ["天津","天津","河西区"];
arr[6] = ["天津","天津","和平区"];
arr[7] = ["天津","天津","南开区"];
arr[8] = ["宁夏","银川","银川区"];
arr[9] = ["宁夏","固原","固原区"];
arr[10] = ["宁夏","石嘴山","石嘴山区"];
arr[11] = ["宁夏","吴忠","吴忠区"];
arr[12] = ["宁夏","吴忠","吴忠新区"];var tab = document.getElementById("tab");
function showcity(tdprov){
//清除前次显示结果
for (var i=tab.rows[1].cells.length-1; i>0; i--)
{
tab.rows[1].removeChild(tab.rows[1].cells[i]);
}
for (var i=tab.rows[2].cells.length-1; i>0; i--)
{
tab.rows[2].removeChild(tab.rows[2].cells[i]);
} var sheng = tdprov.innerHTML;
var last;
for (var i=0; i<arr.length; i++)
{
if (arr[i][prov] == sheng && last != arr[i][city])
{
var newcell = tab.rows[1].insertCell();
newcell.style.cursor = "hand";
newcell.innerHTML = arr[i][city];
newcell.onclick = function(){showdist(this)};
last = arr[i][city];
}
}
}
function showdist(tdcity){
//清除前次显示结果
for (var i=tab.rows[2].cells.length-1; i>0; i--)
{
tab.rows[2].removeChild(tab.rows[2].cells[i]);
}
var cheng = tdcity.innerHTML;
for (var i=0; i<arr.length; i++)
{
if (arr[i][city] == cheng )
{
var newcell = tab.rows[2].insertCell();
newcell.innerHTML = arr[i][dist];
}
}
}
//-->
</SCRIPT>