悬停效果：展开底部边框

Question

我正在尝试在边框上获得 过渡悬停效果 悬停时边框会扩展。

h1 {
  color: #666;
}

h1:after {
  position: absolute;
  left: 10px;
  content: '';
  height: 40px;
  width: 275px;
  border-bottom: solid 3px #019fb6;
  transition: left 250ms ease-in-out, right 250ms ease-in-out;
  opacity: 0;
}

h1:hover:after {
  opacity: 1;
}

<h1>CSS IS AWESOME</h1>

我已经在 Jsfiddle

上试过了

Answer 1

transition: all 1000ms ease-in-out;

Demo

或者您正在寻找这个

Demo2

Answer 2

要在悬停时展开底部边框，您可以使用transform:scaleX'(); (mdn reference) 并在悬停状态下将其从 0 转换为 1。

以下是边框悬停效果的示例：

边框和过渡设置在伪元素上以防止过渡文本并避免添加标记。
要从左或右扩展底部边框，可以将transform-origin property更改为伪元素的左侧或右侧：

h1 { color: #666;display:inline-block; margin:0;text-transform:uppercase; }
h1:after {
  display:block;
  content: '';
  border-bottom: solid 3px #019fb6;  
  transform: scaleX(0);  
  transition: transform 250ms ease-in-out;
}
h1:hover:after { transform: scaleX(1); }
h1.fromRight:after{ transform-origin:100% 50%; }
h1.fromLeft:after{  transform-origin:  0% 50%; }

<h1 class="fromCenter">Expand from center</h1><br/>
<h1 class="fromRight">Expand from right</h1><br/>
<h1 class="fromLeft">Expand from left</h1>

注意：您需要添加供应商前缀以最大化浏览器支持（请参阅 canIuse）。

悬停时展开底部边框 2 行

当文本跨越 2 行时，您可以实现此效果。 before 伪元素绝对定位为第一行下划线 bottom:1.2em;:

h1 { position:relative;color: #666;display:inline-block; margin:0;text-transform:uppercase;text-align:center;line-height:1.2em; }
h1:after, h1:before {
  display:block;
  content: '';
  border-bottom: solid 3px #019fb6;  
  transform: scaleX(0);  
  transition: transform 250ms ease-in-out;
}
h1:before{
  position:absolute;
  bottom:1.2em; left:0;
  width:100%;
}
.ef2:hover:after {
  transition-delay:150ms;
}
  
h1:hover:after, h1:hover:before { transform: scaleX(1); }

<h1>Expand border<br/>on two lines</h1>
<br/>
<br/>
<h1 class="ef2">Expand border<br/>effect two</h1>

悬停进出时的不同过渡方向：

重点是在悬停状态下将变换原点位置从一侧更改为另一侧。这样底部边框 在悬停时从一侧进入并在元素不再悬停时从另一侧退出。
这是一个演示：

h1 { color: #666;display:inline-block; margin:0;text-transform:uppercase; }
h1:after {
  display:block;
  content: '';
  border-bottom: solid 3px #019fb6;  
  transform: scaleX(0);  
  transition: transform 250ms ease-in-out;
}
h1.fromLeft:after{ transform-origin: 100% 50%; }
h1.fromRight:after{  transform-origin:   0% 50%; }
h1.fromLeft:hover:after{ transform: scaleX(1); transform-origin:   0% 50%; }
h1.fromRight:hover:after{ transform: scaleX(1); transform-origin: 100% 50%; }

<h1 class="fromRight">Expand from right</h1><br/>
<h1 class="fromLeft">Expand from left</h1>

Answer 3

我们可以使用简单的过渡效果。

HTML

<h1>CSS IS AWESOME</h1>

CSS

h1 {
    color: #666;
    position: relative;
    display: inline-block;
}

h1:after {
    position: absolute;
    left: 50%;
    content: '';
    height: 40px;
    height: 5px;
    background: #f00;
    transition: all 0.5s linear;
    width: 0;
    bottom: 0;  
}

h1:hover:after {
    width: 270px;
    margin-left: -135px;
}

Link 到 Fiddle

Answer 4

我知道这是一个旧的 post 并且已经回答了，但您可能也喜欢以下效果。

<div class="cd-single-point">
    <a class="cd-img-replace" href="#0"></a>
</div>

   .cd-single-point {
    position: absolute;
    list-style-type: none;
    left: 20px;
    top: 20px;
  }

  .cd-single-point>a {
      position: relative;
      z-index: 2;
      display: block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #0079ff;
      -webkit-transition: background-color 0.2s;
      -moz-transition: background-color 0.2s;
      -o-transition: background-color 0.2s;
      transition: background-color 0.2s;
  }

  .cd-single-point::after {
    content: '';
    position: absolute;
    border-radius: 50%;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    animation: cd-pulse 2s infinite;
  }

  @keyframes cd-pulse
  {
  0%  {box-shadow:0 0 0 0 #0079ff}
  100%{box-shadow:0 0 0 20px rgba(255,150,44,0)}
  }

DEMO

Answer 5

h1 {
  color: #666;
}

h1:after {
  position: absolute;
  left: 10px;
  content: '';
  height: 40px;
  width: 275px;
  border-bottom: solid 3px #019fb6;
  transition: all 550ms ease-in-out;
  border-bottom-width: 0px;
}

h1:hover:after {
  border-bottom-width: 5px;
}

<h1>CSS IS AWESOME</h1>

Answer 6

h1 {
  color: #666;
  display:inline-block;
  margin:0;
  text-transform:uppercase;
 }
h1:after {
  display:block;
  content: '';
  border-bottom: solid 3px #92a8d1;  
  transform: scaleX(0);  
  transition: transform 800ms ease-in-out;
}
h1:hover:after {
 transform: scaleX(1);
}

<h1 class="fromCenter">Hover Over Me</h1><br/>

Answer 7

简洁轻量版

li {
    margin-bottom: 10px;
}

.cool-link {
    display: inline-block;
    color: #000;
    text-decoration: none;
}

.cool-link::after {
    content: '';
    display: block;
    width: 0;
    height: 2px;
    background: #000;
    transition: width .3s;
}

.cool-link:hover::after {
    width: 100%;
    //transition: width .3s;
}

<ul>
    <li><a class="cool-link" href="#">A cool link</a></li>
    <li><a class="cool-link" href="#">A cool link</a></li>
    <li><a class="cool-link" href="#">A cool link</a></li>
</ul>

Answer 8

我们只需要 background 就可以做到这一点。不需要伪元素。这样比较灵活。

h1 {
  /* you can change these variables to control the border */
  --border-color: purple;
  --border-width: 5px;
  --bottom-distance: 0px; /* you can increase this */
  
  color: #666;
  display: inline-block;
  background-image: linear-gradient(var(--border-color), var(--border-color));
  background-size: 0% var(--border-width);
  background-repeat: no-repeat;
  transition: background-size 0.3s;
  margin: 5px 0;
}

.fromCenter {
  background-position: 50% calc(100% - var(--bottom-distance));
}

.fromRight {
  background-position: 100% calc(100% - var(--bottom-distance));
}

.fromLeft {
  background-position: 0 calc(100% - var(--bottom-distance))
}

h1:hover {
  background-size: 100% var(--border-width);
}

<h1 class="fromCenter">Expand from center</h1><br/>
<h1 class="fromRight">Expand from right</h1><br/>
<h1 class="fromLeft">Expand from left</h1>

多行动画：

h1 {
  /* you can change these variables to control the border */
  --border-color: purple;
  --border-width: 5px;
  --bottom-distance: 0px; /* you can increase this */
  
  color: #666;
  display: inline; /* should be 'inline' for multiple line animation */
  background-image: linear-gradient(var(--border-color), var(--border-color));
  background-size: 0% var(--border-width);
  background-repeat: no-repeat;
  transition: background-size 0.5s;
}

.fromCenter {
  background-position: 50% calc(100% - var(--bottom-distance));
}

.fromRight {
  background-position: 100% calc(100% - var(--bottom-distance));
}

.fromLeft {
  background-position: 0 calc(100% - var(--bottom-distance))
}

h1:hover {
  background-size: 100% var(--border-width);
}

<h1 class="fromLeft">Expand from <br>left with <br>multiple line</h1>

Answer 9

h1 {
  /* you can change these variables to control the border */
  --border-color: purple;
  --border-width: 5px;
  --bottom-distance: 0px; /* you can increase this */
  
  color: #666;
  display: inline-block;
  background-image: linear-gradient(var(--border-color), var(--border-color));
  background-size: 0% var(--border-width);
  background-repeat: no-repeat;
  transition: background-size 0.3s;
  margin: 5px 0;
}

.fromCenter {
  background-position: 50% calc(100% - var(--bottom-distance));
}

.fromRight {
  background-position: 100% calc(100% - var(--bottom-distance));
}

.fromLeft {
  background-position: 0 calc(100% - var(--bottom-distance))
}

h1:hover {
  background-size: 100% var(--border-width);
}

<h1 class="fromCenter">Expand from center</h1><br/>
<h1 class="fromRight">Expand from right</h1><br/>
<h1 class="fromLeft">Expand from left</h1>

悬停效果：展开底部边框

Hover effect : expand bottom border

css

border

css-transitions

css-transforms

悬停时展开底部边框 2 行

悬停进出时的不同过渡方向：