PHP Ajax JS省市区三级联动

header("Content-Type: text/html; charset=gb2312");
$conn = new COM("ADODB.Connection") or die("Cannot start ADO");
$connstr = "Provider=SQLOLEDB;Persist Security Info=False;User ID=sa;Password=zzh;Initial Catalog=NoteBook;Data Source=localhost";

if($_REQUEST['ID']==0){//获得省列表
$conn->Open($connstr); //建立数据库连接
$sqlstr = "select name from Province"; //设置查询字符串
$rs = $conn->Execute($sqlstr); //执行查询获得结果
$num_cols = $rs->Fields->Count(); //得到数据集列数
$Province=array();
$i=0;
while (!$rs->EOF) {
$Province[$i]=$rs->Fields['name']->Value.",";
$rs->MoveNext();
$i ;
}
foreach($Province as $val)
echo $val;
$conn->Close();
$rs = null;
$conn = null;
}



if($_REQUEST['ID']>0&&$_REQUEST['ID']<35){//获得省对应的市列表
$conn->Open($connstr); //建立数据库连接
$sqlstr = "select name from City where cid=".$_REQUEST['ID']; //设置查询字符串
$rs = $conn->Execute($sqlstr); //执行查询获得结果
$num_cols = $rs->Fields->Count(); //得到数据集列数
$City=array();
$i=0;
while (!$rs->EOF) {
$City[$i]=$rs->Fields['name']->Value.",";
$rs->MoveNext();
$i ;
}
foreach($City as $val)
echo $val;
$conn->Close();
$rs = null;
$conn = null;
}



if($_REQUEST['ID']>100){//获得省市对应的县列表
$conn->Open($connstr); //建立数据库连接
$sqlstr = "select name from County where cid=".$_REQUEST['ID']; //设置查询字符串
$rs = $conn->Execute($sqlstr); //执行查询获得结果
$num_cols = $rs->Fields->Count(); //得到数据集列数
$County=array();
$i=0;
while (!$rs->EOF) {
$County[$i]=$rs->Fields['name']->Value.",";
$rs->MoveNext();
$i ;
}
foreach($County as $val)
echo $val;
$conn->Close();
$rs = null;
$conn = null;
}
?>