CODEWITHSUNDEEP
csscss-selectors
Ellis Johnston
Ellis Johnston

Reputation: 43

Before and After Hover Effect

I have been scouring the web on before and after effects and I just haven't.. found anything remotely helpful. It's like the gray area of CSS. I was wondering how I would go about doing an effect like on twitter's homepage: This is on the hover effect. https://i.sstatic.net/TJm16.jpg. It has a transition too, but I'm not sure how to implement it. Again i'm not even sure if this is using before and after, I imagine it is hover, but any help would be really appreciated.

Here is my code for my navigation:

<div id="navbar3" class="navbar-collapse collapse">
                <ul class="nav navbar-nav navbar-right">
                  <li class="active"><a href="#">Home</a></li>
                  <li><a href="#">About</a></li>
                  <li><a href="#">Contact</a></li>
                  <li class="dropdown">
                    <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">Dropdown <span class="caret"></span></a>
                    <ul class="dropdown-menu" role="menu">
                      <li><a href="#">Action</a></li>
                      <li><a href="#">Another action</a></li>
                      <li><a href="#">Something else here</a></li>
                      <li class="divider"></li>
                      <li class="dropdown-header">Nav header</li>
                      <li><a href="#">Separated link</a></li>
                      <li><a href="#">One more separated link</a></li>
                    </ul>
                  </li>
                </ul>
              </div>

Upvotes: 2

Views: 10572

Answers (3)

hungerstar
hungerstar

Reputation: 21675

You haven't provided a much detail on the exact thing you're attempting to replicate. I'm going to assume it's the underline that animates up from the bottom of a navigation item.

To do this you will need to use CSS transition.

A simplified version of what Twitter is doing is below. They set a height on the <a> and <li> and add a border to the <a>. Since they have overflow:hidden; applied to the border of the <li> the border they applied to the <a> is initially hidden.

When the <li> is hovered the height of the <a> is reduced. They use transition on the height to animate the border up into view.

ul,
li {
  margin: 0;
  padding: 0;
  list-style: none;
}
li {
  float: left;
  height: 40px;
  overflow: hidden;
}
a {
  display: block;
  height: 40px;
  padding: 0 10px;
  line-height: 40px;
  text-decoration: none;
  overflow: hidden;
  border-bottom: 3px solid #0c0;
  transition: height 250ms ease-in-out;
}
li:hover a {
  height: 37px;
}
<ul>
  <li><a href="#">One</a></li>
  <li><a href="#">Two</a></li>
  <li><a href="#">Three</a></li>
</ul>

Here is another way of animating in the underline with pseudo elements.

ul,
li {
  margin: 0;
  padding: 0;
  list-style: none;
}
li {
  position: relative;
  float: left;
}
a {
  display: block;
  padding: 0 10px;
  line-height: 40px;
  text-decoration: none;
}
a:after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  display: block;
  height: 0;
  width: 100%;
  text-align: center;
  background-color: #0c0;
  transition: height 250ms ease-in-out;
}
li:hover a:after {
  height: 3px;
}
<ul>
  <li><a href="#">One</a></li>
  <li><a href="#">Two</a></li>
  <li><a href="#">Three</a></li>
</ul>

Upvotes: 0

Brian John
Brian John

Reputation: 599

You can definitely use a ::before or you can animate the border/padding and it will create the same grow effect. Working fiddle here: FIDDLE

Upvotes: 0

Zeev Katz
Zeev Katz

Reputation: 2273

You can do it with :after and :before pseudo selector. Im created an example based on your image, its look like this:

@import url('https://fonts.googleapis.com/css?family=Roboto');

body{
  padding: 5%;
}

.exemple {
  font-family: 'Roboto', sans-serif;
  position: relative;
  padding: 2.5% 3.5%;
  text-decoration: none;
  font-size: 0.9em;
  color: #333333;
  transition: ease .1s;
  -webkit-transition: ease .1s;
}

.exemple:before {
  font-family: 'FontAwesome';
  content: '\f0e7';
  font-size: 1.1em;
  margin-right: 10px;
}

.exemple:after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 0px;
  background: #20abe1;
  transition: ease .1s;
  -webkit-transition: ease .1s;
}

.exemple:hover {
  color: #20abe1;
}

.exemple:hover:after{
  height: 4px;
}
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet"/>

<a href="#" class="exemple">Moments</a>

Working Fiddle

Upvotes: 2

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