var someData;
$.ajax({      url: '/prefix/entity1/action1',
      type: 'GET' ,
      async: true,
      contentType: "application/json",
      success: function (resp) {
        //do something on response
        someData.attr1 = resp.attr1;
      },
      error: function (XMLHttpRequest, textStatus, errorThrown) {
        //在这个页面里，所有的请求的错误都做同样的处理
        if (XMLHttpRequest.status == "401") {
          window.location.href = '/login.html';
        } else {
          alert(XMLHttpRequest.responseText);
        }
      }
    });
$.ajax({
      url: '/prefix/entity2/action2',
      type: 'POST' ,
      dataType: "json",
      data: JSON.stringify(someData),
      async: true,
      contentType: "application/json",
      success: function (resp) {
        //do something on response
       },
      error: function (XMLHttpRequest, textStatus, errorThrown) {
        //在这个页面里，所有的请求的错误都做同样的处理
        if (XMLHttpRequest.status == "401") {
          window.location.href = '/login.html';
        } else {
          alert(XMLHttpRequest.responseText);
        }
      }
    });

//url：地址
//data：数据对象，在函数内部会转化成json串，如果没传，表示用GET方法，如果传了，表示用POST方法
function ajax(url, data, callback) {
    $.ajax({
      url: url,
      type: data == null ? 'GET' : 'POST',
      dataType: "json",
      data: data == null ? '' : JSON.stringify(data),
      async: true,
      contentType: "application/json",
      success: function (resp) {
        callback(resp);
      },
      error: function (XMLHttpRequest, textStatus, errorThrown) {
        if (XMLHttpRequest.status == "401") {
          window.parent.location = '/enterprise/enterprise_login.html';
          self.location = '/enterprise/enterprise_login.html';
        } else {
          alert(XMLHttpRequest.responseText);
        }
      }
    });
}

ajax('/prefix/entity1/action1',null, function(resp){
   //do something on response
   someData.attr1 = resp.attr1;
   ajax('/prefix/entity2/action2', someData, function(resp){
     //do something on response
   }
};

function ajax(url, data, callback) {
  var p = new Promise(function (resolve, reject) {
    $.ajax({
      url: url,
      type: data == null ? 'GET' : 'POST',
      dataType: "json",
      data: data == null ? '' : JSON.stringify(data),
      async: true,
      contentType: "application/json",
      success: function (resp) {
        callback(resp);
        resolve();
      },
      error: function (XMLHttpRequest, textStatus, errorThrown) {
        if (XMLHttpRequest.status == "401") {
          window.parent.location = '/enterprise/enterprise_login.html';
          self.location = '/enterprise/enterprise_login.html';
        } else {
          alert(XMLHttpRequest.responseText);
        }
        reject();
      }
    });
  });
  return p;
}

ajax('/prefix/entity1/action1',null, function(resp){
   //do something on response
   someData.attr1 = resp.attr1;
}).then(
   ajax('/prefix/entity2/action2', someData, function(resp){
     //do something on response
   }
).then(
   initVue() ;
).then(
   //do something else
)