FadeInUp css animation not working

问题

I made attempts to create a CSS animation, when you hover over the box, it reveals the div using CSS animations. I have used the following site as reference. click here however i can't seem to achieved the efx. On my site i have use JqUERY for a show and hide function, my addClass and RemoveClass works however overall the function isn't working how it should do. Can someone guide me in the right direction.

/** HTML **/

div class="box">
        <div class="trigger">hhh</div>
            <div class="overlay">
                <h1>box 1</h1>
            </div>
        </div>

<div class="box">
<div class="trigger">hhh</div>
      <div class="overlay">
            <h1>box 1</h1>
        </div>
    </div>

<div class="box">
<div class="trigger">hhh</div>
    <div class="overlay">
            <h1>box 1</h1>
        </div>
    </div>

/* jquery **/

                     $(".overlay").addClass("visible");
        $(".overlay").removeClass("visible");
            $(".trigger").hover(function(){
                var $this = $(this);
                $this.next(".overlay").addClass("visible");
            }); 

            $(".trigger").mouseleave(function(){
                var $this = $(this);
                $this.next(".overlay").removeClass("visible");
            }); 

/** CSS ANIMATION **/

.fadeInDown {
-webkit-animation-name: fadeInDown;
-moz-animation-name: fadeInDown;
-o-animation-name: fadeInDown;
animation-name: fadeInDown;
-webkit-animation-duration: 1s;
-webkit-animation-delay: 2s;
-webkit-animation-timing-function: ease;
-webkit-animation-fill-mode: both;

-moz-animation-duration: 1s;
-moz-animation-delay: 2s;
-moz-animation-timing-function: ease;
-moz-animation-fill-mode: both;

-o-animation-duration: 1s;
-o-animation-delay: 2s;
-o-animation-timing-function: ease;
-o-animation-fill-mode: both;

animation-duration: 1s;
animation-delay: 2s;
animation-timing-function: ease;
animation-fill-mode: both;
    }


     @-webkit-keyframes fadeInDown {
0% {
    opacity: 0;
    -webkit-transform: translateY(-20px);
}

100% {
    opacity: 1;
    -webkit-transform: translateY(0);
}
      }


     .fadeInUp {
-webkit-animation-name: fadeInUp;
-moz-animation-name: fadeInUp;
-o-animation-name: fadeInUp;
animation-name: fadeInUp;
-webkit-animation-duration: 1s;
-webkit-animation-delay: 2s;
-webkit-animation-timing-function: ease;
-webkit-animation-fill-mode: both;

-moz-animation-duration: 1s;
-moz-animation-delay: 2s;
-moz-animation-timing-function: ease;
-moz-animation-fill-mode: both;

-o-animation-duration: 1s;
-o-animation-delay: 2s;
-o-animation-timing-function: ease;
-o-animation-fill-mode: both;

animation-duration: 1s;
animation-delay: 2s;
animation-timing-function: ease;
animation-fill-mode: both;
        }

      @-Webkit-keyframes fadeInUp {
0% {
    opacity: 0;
    -moz-transform: translateY(20px);
}

回答1:

Try using the css classes that you have provided, and pass a second parameter to the "addClass" call indicating the number of milliseconds that it should animate. For example:

$(".trigger").hover(function(){
    var $this = $(this);
    $this.next(".overlay").addClass("fadeInDown", 1000);
}); 

回答2:

Add following css and HTML tag .

HTML code:-

<h1 class="animated fadeInUp" >Example</h1>

CSS code:-

.animated {
  -webkit-animation-duration: 1s;
  animation-duration: 1s;
  -webkit-animation-fill-mode: both;
  animation-fill-mode: both;
}
@keyframes fadeInUp {
  from {
    opacity: 0;
    -webkit-transform: translate3d(0, 100%, 0);
    transform: translate3d(0, 100%, 0);
  }

  to {
    opacity: 1;
    -webkit-transform: none;
    transform: none;
  }
}

.fadeInUp {
  -webkit-animation-name: fadeInUp;
  animation-name: fadeInUp;
}

来源：https://stackoverflow.com/questions/18337404/fadeinup-css-animation-not-working