利用css实现鼠标经过元素，下划线由中间向两边展开

代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>鼠标移入下划线展开</title>
<style type="text/css">
#underline{
    width: 200px;
    height: 50px;
    background: #ddd;
    margin: 20px;
    position: relative;
}

#underline:after{
    content: "";
    width: 0;
    height: 1px;
    background: blue;
    position: absolute;
    top: 100%;
    left: 50%;
    transition: all .8s;
}

#underline:hover:after{
   left: 0%;
   width: 100%;
}
</style>

</head>

<body>

    <div id="underline"></div>

</body>

</html> 


参考文：https://blog.csdn.net/qq_31648761/article/details/72953434?locationNum=9&fps=1


方法二：
<a href=‘‘ class=‘ui-box bottom-inOutSpread‘>Audio Description</a>

css：
.ui-box {
    text-decoration:none;
    border:none;
    font-family:‘Roboto‘, sans-serif;
    font-size:14px;
    position:relative;
    vertical-align:baseline;
    padding:10px
}
.bottom-inOutSpread:before,.bottom-inOutSpread:after,.bottom-inOutSpread>.ui-border-element:before,.bottom-inOutSpread>.ui-border-element:after {
    content:‘‘;
    position:absolute
}
.bottom-inOutSpread:after {
    border-bottom:2px solid #333;
    left:51%;
    right:51%;
    bottom:0px;
    -webkit-transition-property:all;
    -moz-transition-property:all;
    -o-transition-property:all;
    transition-property:all;
    -webkit-transition-timing-function:cubic-bezier(0, 0.98, 0.51, 0.93);
    -moz-transition-timing-function:cubic-bezier(0, 0.98, 0.51, 0.93);
    -o-transition-timing-function:cubic-bezier(0, 0.98, 0.51, 0.93);
    transition-timing-function:cubic-bezier(0, 0.98, 0.51, 0.93);
    -webkit-transition-duration:200ms;
    -moz-transition-duration:200ms;
    -o-transition-duration:200ms;
    transition-duration:200ms;
    -webkit-transition-delay:0s;
    -moz-transition-delay:0s;
    -o-transition-delay:0s;
    transition-delay:0s
}
.bottom-inOutSpread:hover:after {
    left:0%;
    right:0%
}
.bottom-inOutSpread:not(:hover):after {
    -webkit-transition-delay:0s;
    -moz-transition-delay:0s;
    -o-transition-delay:0s;
    transition-delay:0s
}
原文：http://www.cnblogs.com/HONGYE1994/p/8012093.html
posted @ 2018-08-26 17:49  smuwgeg  阅读(799)  评论(0)  编辑  收藏  举报