Ext同步与异步请求（转自garnettcwm）

EXTJS 同步和异步请求

同步方式请求：

1. var  conn = Ext.lib.Ajax.getConnectionObject().conn;
2. conn.open( "GET" ,  'your url' , false );
3. conn.send( null );
4. alert(conn.responseText);
5. var respText = Ext.decode(conn.responseText);  //若符合JSON规范，转化为JSON数组

或者

1. var conn = Ext.lib.Ajax.getConnectionObject().conn;
2. conn.open("POST", url, false);
3. conn.send("发送到服务器端的信息");
4. data = conn.responseText;
5. alert(data);
6. var respText = Ext.decode(conn.responseText);  //若符合JSON规范，转化为JSON数组

关键是要设置false这个参数

异步方式请求：

1. Ext.Ajax.request({
2.             url :  'listpublishersms.action' ,
3.             success :  function (response, options) {
4.                            var  temp =  "<chart caption='"
5.                             + startField.getValue().dateFormat( "Y-m-d" )
6.                             +  "至"
7.                             + endField.getValue().dateFormat( "Y-m-d" )
8.                             +  "' baseFontSize='12' formatNumberScale='0' showBorder='1'>" ;
9.                              var  responseArray = Ext.util.JSON
10.                                     .decode(response.responseText);
11.                             alert(responseArray.list.length);
12.                              for  ( var  i = 0;i < responseArray.list.length ;i++) {
13.                                         var  pname = responseArray.list[i].pname;
14.                                          var  count = responseArray.list[i].count;
15.                                         temp +=  "<set label='"  + pname
16.                                             +  "' value='"  + count +  "'/>" ;
17.                             }
18.                             temp +=  "</chart>" ;
19.                             chart_chart.setDataXML(temp);
20.                         }
21.                     }); 

Ext.decode()是将json字符串转换成对象;Ext.encode()是将对象转换成json字符串