CSS动画延迟不触发

Question

只是好奇地想知道为什么这个简单的动画延迟似乎无法工作。我只想在元素淡入之前延迟7s。很简单，我确定，但已经看了很久了。

​

.box1 {
  width: 100px;
  margin: 0 auto;
  position: relative;
  border: 1px solid blue;
}
.box2 {
   background: red;
  color: black;
  text-align: center;
  animation-delay: 7s;
  -webkit-animation-delay: 7s;
  animation: fadein 2s linear;
  -webkit-animation: fadein 2s linear;
 
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

<div class= "box1">

  <div class="box2">

    <p>some text</p>

  </div>

</div>

​

Answer 1

尝试使用长格式animation属性：

• animation-delay
• animation-name
• animation-duration
• animation-timing-function

​

.box1 {
  width: 100px;
  margin: 0 auto;
  position: relative;
  border: 1px solid blue;
}
.box2 {
   background: red;
  color: black;
  text-align: center;
  opacity: 0;
  -webkit-animation-delay: 7s;
  -webkit-animation-name: fadein;
  -webkit-animation-duration: 2s; 
  -webkit-animation-timing-function: linear;
  animation-delay: 7s;
  animation-name: fadein; 
  animation-duration: 2s;
  animation-timing-function: linear;
 
}
@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

<div class= "box1">

  <div class="box2">

    <p>some text</p>

  </div>

</div>

​

Answer 2

将动画延迟放在动画之后，因为延迟需要附加到所讨论的动画(顺序很重要)：

​

.box1 {
  width: 100px;
  margin: 0 auto;
  position: relative;
  border: 1px solid blue;
}
.box2 {
   background: red;
  color: black;
  text-align: center;
  -webkit-animation: fadein 2s linear;
   animation: fadein 2s linear; 
  -webkit-animation-delay: 7s;
   animation-delay: 7s;
 
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

<div class="box1">

  <div class="box2">

    <p>some text</p>

  </div>

</div>

​

或者使用速记方式，删除animation-delay: 7s;和-webkit-animation-delay: 7s;，并将延迟时间添加到animation属性中，如下所示：

-webkit-animation:fadein 2s linear 7s;
 animation:fadein 2s linear 7s;

​

.box1 {
  width: 100px;
  margin: 0 auto;
  position: relative;
  border: 1px solid blue;
}
.box2 {
  background: red;
  color: black;
  text-align: center;
  -webkit-animation: fadein 2s linear 7s;
  animation: fadein 2s linear 7s;
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

<div class="box1">

  <div class="box2">

    <p>some text</p>

  </div>

</div>

​

Answer 3

下面的代码工作，我将框的初始不透明度设置为0，这样它就“消失了”，而且只有在动画本身之后声明它时，动画延迟属性才能工作。我还添加了动画-填充模式:转发；以保持框后显示动画。

​

.box1 {
  width: 100px;
  margin: 0 auto;
  position: relative;
  border: 1px solid blue;
}
.box2 {
   background: red;
  color: black;
  text-align: center;
  animation: fadein 2s linear;
  -webkit-animation: fadein 2s linear;
  animation-delay: 7s;
  -webkit-animation-delay: 7s;
  animation-fill-mode: forwards;
  -webkit-animation-fill-mode: forwards;
  opacity: 0;
 
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

<div class= "box1">

  <div class="box2">

    <p>some text</p>

  </div>

</div>

​