Complete Intro to Web Dev v3

Watch on Frontend Masters

CSS animations are a deep pool of knowledge and we're just going to look at a few of the techniques. You can achieve some truly amazing things with just CSS animations. You can also use JavaScript with CSS to make anything you can imagine.

<style>
  @keyframes spin {
    to {
      transform: rotate(360deg);
    }
  }
  .spinny-boi {
    animation: spin 0.5s infinite linear;
    display: inline-block;
    font-size: 30px;
  }
</style>
<div class="spinny-boi">🤢</div>
  • The @keyframes part allows you to define a reusable animation. We could throw spin on anything now.
  • We just definte to which is what you want the end state of your animation state to be. We could define from too which is where you want your animation to start from. Implicitly if you don't define a from, your animation starts from where it is already. In this case, the spinny-boi isn't rotated at all, or transform: rotate(0deg). So it will rotate from 0 t0 360, or a full revolution. Feel free to play with it.
  • animation is the property to use a defined keyframe. Here we just say "do what spin defines, the whole animation should take a half second, do it infinitely (aka never stop), and do it in a linear fashion (so there's no speed-up or speed-down in the animation). This is a short hand. You can define the properties separately. See the MDN here.

Easing

Animation implies some sort of change over time. You're going from 0 to 1 in some capacity. The rate of change can be manipulated to achieve some cool effects. In the previous example you saw a linear function (these effects are called functions) where it's just a smooth line between 0 and 1. Let's check out the other possibilities.

<style>
  @keyframes move {
    to {
      translate: 50px;
    }
  }
  .dancer {
    display: inline-block;
    font-size: 30px;
    position: absolute;
    right: 0;

    /*
    this is the long way of doing:
    animation: move 1s infinite alternate;
    */
    animation-name: move;
    animation-duration: 1s;
    animation-iteration-count: infinite;
    animation-direction: alternate;
  }

  .dancers-list {
    width: 100%;
    max-width: 300px;
    position: relative;
  }

  .linear {
    animation-timing-function: linear;
  }
  .ease {
    animation-timing-function: ease;
  }
  .ease-in-out {
    animation-timing-function: ease-in-out;
  }
  .ease-in {
    animation-timing-function: ease-in;
  }
  .ease-out {
    animation-timing-function: ease-out;
  }
  .cubic-bezier {
    animation-timing-function: cubic-bezier(0,1,.5,1);
  }
</style>

<ul class="dancers-list">
  <li>linear: <span class="dancer linear">💃</li>
  <li>ease: <span class="dancer ease">💃</li>
  <li>ease-in-out: <span class="dancer ease-in-out">💃</li>
  <li>ease-in: <span class="dancer ease-in">💃</li>
  <li>ease-out: <span class="dancer ease-out">💃</li>
  <li>cubic-bezier: <span class="dancer cubic-bezier">💃</li>
</ul>

Notice all of them some sort of what we'd call "rubber-banding" effect where it speeds up and slows down in some way. Imagine we could use ease-out to simulate the gravity of a bouncing ball or something like that.

The last one, cubic-bezier allows you to define your own curve via mathematics that I don't understand well enough to explain to you. But I wanted to show you if you have exact needs that one of the functions doesn't fit you can accomplish with cubic-bezier.

Read more on the MDN here

Beyond Positioning

I've been showing you how to do this with positioning since it's the easiest to visualize. Many CSS properties are able to be animated so let's see one example here.

<style>
  @keyframes rainbow {
    100%,
    0% {
      color: rgb(255, 0, 0);
    }
    8% {
      color: rgb(255, 127, 0);
    }
    16% {
      color: rgb(255, 255, 0);
    }
    25% {
      color: rgb(127, 255, 0);
    }
    33% {
      color: rgb(0, 255, 0);
    }
    41% {
      color: rgb(0, 255, 127);
    }
    50% {
      color: rgb(0, 255, 255);
    }
    58% {
      color: rgb(0, 127, 255);
    }
    66% {
      color: rgb(0, 0, 255);
    }
    75% {
      color: rgb(127, 0, 255);
    }
    83% {
      color: rgb(255, 0, 255);
    }
    91% {
      color: rgb(255, 0, 127);
    }
  }
  .rainbow-boi {
    animation: rainbow 4s infinite linear;
    font-size: 30px;
  }
</style>
<div class="rainbow-boi">Rainbow</div>
  • Similar idea but with color. Lots of things can be animated, like size and position.
  • from is an alias for 0% and to is an alias for 100%. You can define percentages like we did here.

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