三级联动

html:

<form name="form" method="GET" action="admin_search.php">
<div class="Line">
<div class="variety"><label for="groupid">市:</label>
<select name="groupcity" id="groupcity" onchange="test()">
<option value="0">请选择</option>
<{foreach from=$grouparray item=item}>
<option value="<{$item.group_id}>"><{$item.group_name}></option>
<{/foreach}>
</select>
</div>
<div class="variety"><label for="groupid">区:</label>
<select name="groupid1" id="groupid1" onchange="test1()">
<option value="0" class="a1">请选择</option>
</select>
</div>
<div class="variety"><label for="groupid">街道:</label>
<select name="groupid2" id="groupid2" >
<option value="0" class="a11">请选择</option>
</select>
</div>
<div class="variety"><label for="no">所属机构</label>
<input type="text" id="no" name="no"></div>
</div>
<div class="searchResult" style="margin-top:20px;">
<input name="searchResult" type="submit" value="查询" >
</div>
</form>

js:

<script>

function test(){
var city= $('#groupcity').val();

$.ajax({
type : "GET", //提交方式
url : "admin_search.php?action=search&city="+city,//路径
dataType:"json",
success : function(result) {//返回数据根据结果进行相应的处理
var html ="";

$.each(result,function(index,comment){
html +="<option value="+comment.group_id+">"+comment.group_name+"</option>";

});
$('#groupid1:not(.a1)').find('option').remove();
$('#groupid1').append(html);
}

});
}
function test1(){
var city1= $('#groupid1').val();

$.ajax({
type : "GET", //提交方式
url : "admin_search.php?action=search&city1="+city1,//路径
dataType:"json",
success : function(result) {//返回数据根据结果进行相应的处理
var html ="";

$.each(result,function(index,comment){
html +="<option value="+comment.group_id+">"+comment.group_name+"</option>";

});

$('#groupid2:not(.a11)').find('option').remove();
$('#groupid2').append(html);
}

});
}

</script>

控制器：

if ($_GET['city']) {
$search1 =" and group_fatherid =".$_GET['city'];

$grouparray1 = @$basedata->GetGrouparray($search1);

if ($grouparray1){
for ($i=0; $i <sizeof($grouparray1) ; $i++) {
$grouparray1[$i]['group_name'] =iconv('GB2312','utf-8',$grouparray1[$i]['group_name']);

}
echo json_encode($grouparray1);
}else{
echo 2;
}
}
if ($_GET['city1']) {
$search2 =" and group_fatherid =".$_GET['city1'];

$grouparray2 = @$basedata->GetGrouparray($search2);

if ($grouparray2){
for ($i=0; $i <sizeof($grouparray2); $i++) {
$grouparray2[$i]['group_name'] =iconv('GB2312','utf-8',$grouparray2[$i]['group_name']);

}
echo json_encode($grouparray2);
}else{
echo 2;
}
}