JSFiddle - React, Tailwind, and code Playground

JavaScript

  var wait = function(){

    var dtd = $.Deferred(); //在函数内部,新建一个Deferred对象

    var tasks = function(){

      alert("执行完毕!");

      dtd.resolve(); // 改变Deferred对象的执行状态

    };
 
    setTimeout(tasks,5000);

    return dtd.promise(); // 返回promise对象

  };

  $.when(wait())

  .done(function(){ alert("哈哈,成功了!"); })

  .fail(function(){ alert("出错啦!"); });