gistfile1.js

var async_task = function (msg, delay) {
  var dfd = $.Deferred();
  setTimeout( function () {
    if ( msg !== 'l' ) {
      dfd.resolve('resolved:' + msg);
    }
    else {
      dfd.reject('rejected:' + msg);
    }
  }, delay);
  return dfd;
};

// This "then" style works only for jQuery 1.8 or above.
// For 1.7 or below, use deferred.pipe() instead.
// See http://api.jquery.com/deferred.then/#entry-longdesc for more detail.
$.when( async_task('h', 2000) )
  .then( function (ret) {
      console.log('success', ret);
      return async_task('o', 2000);
    }, function (ret) {
      console.log('\\(^o^)/', ret);
  })
  .then( function (ret) {
      console.log('success', ret);
      return async_task('l', 2000);
    }, function (ret) {
      console.log('-(^o^)-', ret);
  })
  .then( function (ret) {
      console.log('success', ret);
      return async_task('a', 2000);
    }, function (ret) {
      console.log('/(^o^)\\', ret);
  })
;