easyui combobox 动态加载的两种方法

reload 方法 

javascript代码

    //指定id 和 text  否则始终选择第一个
    $('#contact_city').combobox({ 
         valueField:'id',
        textField:'text'
    });

    $('#contact_province').combobox({
         onSelect: function (data) {var url = "Ajax-index.php?module=Contact&action=Ajax_Contact_Province_Change"+"&contact_province=" +data.text;
                $('#contact_city').combobox('reload', url);
           }
    });

php代码 
       
       $province =trim($_GET['contact_province']);
       $select="SELECT p.province,c.id,c.city,p.provinceid  from  province as p JOIN city as c ON p.provinceid = c.provinceid where p.province='" . $province . "'";

　　　　 $result=$db->query($select);
        $Select_Option="";
        while($row=$db->fetch_array($result)){
            $key=$row[1];
            $value=$row[2];
          
            if($Select_Option==""){
                $Select_Option=  '{"id":"'.$key.'","text":"'.$value.'"}' ;   
            }else{
                $Select_Option=$Select_Option .",". '{"id":"'.$key.'","text":"'.$value.'"}' ;
            }
        }
        $Select_Option="[" . $Select_Option ."]";
        echo $Select_Option;

loadData 方法

javascript 

$(function(){
    $('#contact_city').combobox({    
              valueField:'id',
              textField:'text',
              editable:false  //是否可编辑
         });
 })

$(document).ready(function () {
        $("#contact_province").combobox({
            onChange: function (newVal,oldVal) {
                
                var contact_province=newVal;
                $.ajax({
                    type: "POST",
                    url: "Ajax-index.php?module=<{$module_name}>&action=Ajax_Contact_Province_Change",
                    dataType: "json",
                    data: {"contact_province":contact_province },
                    beforeSend: function(){
                        //$('<div id="msg" />').addClass("loading").html("加载中...").css("color","#999").appendTo('.sub1');
                    },
                    success: function(json){
                        if(json.success==1){
                            //alert(json.msg);
                            var data = $.parseJSON(json.msg); 
                            $("#contact_city").combobox("loadData", data);
                            $("#contact_city ").combobox('select',data[0].text);//默认选中第一项
                        }else{
                            $.messager.alert('消息','数据加载失败!','error'); 
                            return false;
                        }
                    }
               });
            }
        });
    });

PHP代码 

        $province =trim($_POST['contact_province']);
 
        $select="SELECT p.province,c.city,p.provinceid  from  province as p JOIN city as c ON p.provinceid = c.provinceid where p.province='" . $province . "'";
 
        $result=$db->query($select);
        $Select_Option="";
        while($row=$db->fetch_array($result)){
            $value=$row[1];
           
            if($Select_Option==""){
                $Select_Option=  '{"id":"'.$value.'","text":"'.$value.'"}' ;   
            }else{
                $Select_Option=$Select_Option .",". '{"id":"'.$value.'","text":"'.$value.'"}' ;
            }
        }
        $Select_Option="[" . $Select_Option ."]";

        $arr['success'] = 1;
        $arr['msg'] = $Select_Option; 
        echo json_encode($arr);