Question

随着div的顶部在视口中变得可见，我希望在列表项中添加“不透明”类，并在div离开视口后删除该类。

我相信它将包含此jquery，但我只是无法确定哪个函数会根据视口中的div位置触发这些动作

 $('.div-one').addClass('opacity');
   }
  else{
  $('.div-one').removeClass('opacity');
  }
});

这是我的代码

HTML

<div class="container">
<div class="wrapper"> 
<ul>
<div class="one"> 
  <li>Div One</li>
<div>
<div class="two">  
  <li>Div Two</li>
</div>
<div class="three">  
  <li>Div Three</li>
</div>
<div class="four">  
  <li>Div Four</li>
</div>
<div class="five">
  <li>Div Five</li>
</div>  
</ul>
</div>

<div class="image-div">
<div class="div-one">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSdQoevUP6DXp2yIhVspPDq8el3PTNKpOfwJ-V6my_0Mzd2Rs0x"/>  
</div>

<div class="div-two">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRWSzMWTzcJSQdlbu60e0_HK8QntmkoQWrpa1tVjc4EJ7YEDcbHgw"/>  
</div> 

<div class="div-three">
  <img src="http://ftadjusting.com.au/adjusting/wp-content/uploads/2015/09/tl5za8a.png"/>  
</div> 

<div class="div-four">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSIlN2dswdMe3p6mN9LOznw6IiKh26pkCUMnVdf75nMCFsICqY5"/>  
</div> 

<div class="div-five">
  <img src="https://static-media.fxx.com/img/FX_Networks_-_FXX/684/907/Simpsons_12_06_P1_640x360_316723267976.jpg"/>  
</div> 
</div>
</div>

CSS

.wrapper {
  position: fixed;
}

.image-div {
  float: right;
  width: 50vw;
}

.image-div img {
  width: 50vw;
}

.image-div div {
  padding-bottom: 500px;
}

.wrapper ul li {
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 3em;
}

.opacity {
  opacity: 0.4;
  -webkit-transition: all 0.3 ease;
  transition: all 0.3 ease;
}

Answer 1

您不需要jQuery。您可以使用一些简单的JavaScript本身来做到这一点。

希望这会有所帮助：

var isInViewport = function (elem) {
    var bounding = elem.getBoundingClientRect();
    return (
        bounding.top >= 0 &&
        bounding.left >= 0 &&
        bounding.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
        bounding.right <= (window.innerWidth || document.documentElement.clientWidth)
    );
};

var h1 = document.querySelector('h1');
window.addEventListener('scroll', function (event) {
	if (isInViewport(h1)) {
		  console.log("Found...")
	}else{
    console.log('Missing..')
  }
}, false);

body{
  overflow: scroll;
  height: 200vh;
}

<h1>Header</h1>

您现在可以使用 isInViewport 条件设置元素的不透明度。

div进入视口后如何添加类，div离开视口后如何删除类？

1 个答案: