zzcx_line/coding/st-xm/Model/channel/city.php

<?php 
    $id = $_POST['id'];
    $sql = "select ID,AREA_NAME from base_area where PARENT_ID = $id";
    $result=$pdo->query($sql);
    $city = $result->fetchAll(PDO::FETCH_ASSOC);

    $code = 0;
    $info = 'success';
    $massge = '成功';

    $json['code'] = $code;
    $json['info'] = $info;
    $json['massge'] = $massge;
    $json['list'] = $city;
    echo json_encode($json);
?>