jquery 回调失败的情况

node2:/django/mysite/static/Js/Public#cat displaytestxhr.js 
function B (response,status,xhr){
  console.log(response);
  console.log(status);
  console.log(xhr);
  $("#aa").css("background-color","red");
};
$(document).ready(function(){
$("#elem").load('/testxhr/',{Action:"post",aa:3,b:4,c:6},function(response,status,xhr){
 console.log(status);
 if (status=="success")
      { $("#aa").css("background-color","red");
}
else{alert (status+'请求失败')};
})
});