//啟動時遮照
Ext.Ajax.on('beforerequest', function () {
    Ext.getBody().mask("Loading");
}, this);
//結束時移除遮照
Ext.Ajax.on('requestcomplete', function () {
    Ext.getBody().unmask();
}, this);
var paramObj = new Object();
paramObj.id = "123";
//Ext.getBody().mask("Loading2");
Ext.Ajax.request({
    url: "MyAjax.jsp",
    scope: this,
    method: "post",
    success: function (
    response) {
        Ext.getBody()
            .unmask();
        var json = Ext.decode(response.responseText);
        //{success:false|true,msg:'訊息'}
        if (json.success) {
            //回傳success要做的事
        } else {
            //錯誤時alert
            alert(json.msg);

        }

    }, // .createDelegate(this),
    failure: function () {
        if (action.response.status == 200) {

            var json = Ext.decode(action.response.responseText);
            Ext.MessageBox.alert(json.msg);
        } else Ext.MessageBox.alert("Save Error~");
    },

    params: paramObj
});