Edit in JSFiddle

var des = []; //用來放Deferred或Promise物件的array
var deferred;

deferred = $.Deferred();
des.push(deferred.promise()); 
//也可以寫成des.push(deferred)，deferred.promise()回傳的為Promise物件，為不可修改狀態只供查詢狀態的物件，即沒有resolve()等方法
//
$('#anim1').addClass('animClass').one('animationend', resolveDeferred(deferred));

deferred = $.Deferred();
des.push(deferred.promise());
$('#anim2').animate({
  paddingLeft: "-=100%"
}, 9000, resolveDeferred(deferred));

deferred = $.Deferred();
des.push(deferred.promise());
$('#anim3').animate({
  paddingLeft: "-=100%"
}, 5000, resolveDeferred(deferred));
//因為$.when()只能接收一個一個用逗號分開的參數，所以利用apply來將array以個別
//參數的方式傳給when()，when()可接受Deferred及Promise物件
$.when.apply($, des).done(function() {
  $('#text').html($('#text').html() + '<br/>All finished!');
});
//也可以寫成以下，then可以給兩個參數，第一個為done()的callback函式，
//第二個為fail()的callback函式
//$.when.apply($, des).then(function(){
//	$('#text').html($('#text').html() + '<br/>All finished!');
//});

function resolveDeferred(deferred) {
  return function() {
    $('#text').html($('#text').html() + '<br/>#' + this.id + ' finished!');
    deferred.resolve();
  }
}

<div class='animSection'>
  <div id='anim1'>Watch me move1</div>
  <div id='anim2'>Watch me move2</div>
  <div id='anim3'>Watch me move3</div>
</div>
<br/>
<div id='text' class="text">Detect Result:</div>

.animSection div{
  padding-left: 100%;
}

.animClass {
  animation-name: myAnim;
  animation-duration: 6s;
  animation-fill-mode: forwards;
}

@keyframes myAnim {
  0% {
    padding-left: 100%;
  }
  100% {
    padding-left: 0%;
  }
}