javascript - animate() 并不总是有效

Question

我正在尝试使用 jQuery 创建一个简单的 slider 。

$('.next').on('click', function() {
    $('li').animate({'right': '400px'}, 300);
});

$('.back').on('click', function() {
    $('li').animate({'left': 0}, 300);
});

问题是，当我单击带有 next 类的底部时，它只滑动一次，第二次单击不起作用。

我该如何解决这个问题？

https://jsfiddle.net/6t1wx95f/

Answer 1

简单，接下来是 $('li').animate({'left': '-=400px'}, 300);。

$('.next').on('click', function() {
	$('li').animate({'left': '-=400px'}, 300);
});

$('.back').on('click', function() {
 if(parseInt($('li').css('left')) <= 0){
  if(parseInt($('li').css('left')) >= -400){
   $('li').animate({'left': "0"}, 300);
  } else {
   $('li').animate({'left': '+=400px'}, 300);
  }
 }
});

.slider {
  overflow: hidden;
  width: 500%;
}

.slider ul {
  width: 500%;
}

.slider ul li {
  float: left;
  list-style: none;
  position: relative;
  transition: all 0.65s;
}

.next,
.back {
  width: 100px;
  padding: 5px;
  text-align: center;
  background-color: skyblue;
  float: left;
  margin: 10px;
  cursor: pointer;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="slider">
  <ul>
    <li>
      <img src="http://keenthemes.com/preview/metronic/theme/assets/global/plugins/jcrop/demos/demo_files/image1.jpg" alt="" class="active">
    </li>
    <li>
      <img src="https://www.w3schools.com/css/img_lights.jpg" alt="">
    </li>
    <li>
      <img src="http://keenthemes.com/preview/metronic/theme/assets/global/plugins/jcrop/demos/demo_files/image2.jpg" alt="">
    </li>
    <li>
      <img src="http://images.all-free-download.com/images/graphiclarge/a_london_cityscape_515129.jpg" alt="">
    </li>
    <li>
      <img src="https://image.jimcdn.com/app/cms/image/transf/dimension=1920x400:format=jpg/path/s86d6d6c688ca86fa/image/ie4265a3cd27b2997/version/1451246087/image.jpg" alt="">
    </li>
  </ul>
</div>

<div class="back">Back</div>
<div class="next">Next</div>