website/content/blog/2015-05-23-animatable-border.md

---
id: 85
title: 'Animatable: Border'
date: 2015-05-23T19:59:25+00:00
author: Brandon Rozek
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guid: http://brandonrozek.com/?p=85
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This is part 1 of an animation series I’m doing. It is inspired by Lea Verou’s talk called “[The Humble Border-Radius.](https://www.youtube.com/watch?v=JSaMl2OKjfQ)” I looked at her site and she has a good demo of a bunch of different animations [here](http://lea.verou.me/2011/10/animatable-a-css-transitions-gallery/). My goal here is to create a more comprehensive guide to these different animatable properties–mainly for future reference. Animations play a big part in adding interactivity to the web, so why not explore some possible options?

<!--more-->

This post follows well along with my Codepen [demo](http://codepen.io/brandonrozek/full/waWMWR/){.broken_link}, where I&#8217;ll state the box number that applies to what I&#8217;m talking about. \*\*Initial values must be explicitly stated, implicit initial values are generally ignored in animation\*\* \*\\*\*In English terms, you must have already stated a value for what you are animating before you animate it\*\**

### Border-color {#border-color}

  * Accepts 1 to 4 color values
  * Each value corresponds to each side of the border (starting from the top and going clockwise)
  * Initial Value: currentColor

Border-color animates by splitting the colors to their red, green and blue components and raises/lowers them to it&#8217;s new value. ([Demo](http://codepen.io/brandonrozek/pen/PqzPMe){.broken_link}) ([Spec](http://www.w3.org/TR/css3-transitions/#animtype-color)) Example of animation corresponds to #1 in the pen, but I will rewrite the relevant code here.

```css
@keyframes color {
    to { border-color: purple red green blue; }
}

.border-color {
    border-color: white;
    animation: color .4s ease-in .1s infinite alternate;
}
```

 

### Border-radius {#border-radius}

  * Accepts 1 to 4 values for both horizontal and vertical radii
  * Each value corresponds to a corner starting from the top left and going clockwise
  * Initial Value: 0

```css
.border-radius {
    border-radius: 40% 30% 60% 50% / 20% 40% 60% 80%;
    /** is the same as **/
    border-top-left-radius: 40% 20%;
    border-top-right-radius: 30% 40%;
    border-bottom-right-radius: 60% 60%;
    border-bottom-left-radius: 50% 80%;
    /** where the first value is the horizontal
    radius and the second value the vertical radius **/
}
```

For animation, this corresponds to #2 in the pen I made at the top. I&#8217;ll repeat the relevant code here.

```css
@keyframes radius {
    to { border-radius: 20%; }
}

.border-radius {
    border-radius: 0;
    animation: radius .5s ease-in .1s infinite alternate;
}
```

 

### Border-width {#border-width}

  * Accepts 1 to 4 values
  * Each value corresponds to a side of the border (starting from the top and going clockwise)
  * Initial Value: medium

For animation, this corresponds to #3 in the pen I made at the top. I&#8217;ll repeat the relevant code here.

```css
@keyframes width {
    to { border-width: .15rem .25rem .15rem .25rem; }
}

.border-width {
    border-width: .7rem;
    animation: width .5s ease-in .1s infinite alternate;
}
```

 

### Conclusion

Animations are quite enjoyable. The last box in my Codepen demo tries combining all three of those animations. (Super Wacky!)  You don&#8217;t need to use keyframe animations to achieve this, you can also use the transition property. I used keyframes so you can better visualize what&#8217;s going on. There are plenty of other animatable properties to go through, so I&#8217;ll get started on those. In the meantime, if you want to look at some of the sites I used for research I&#8217;ll include the links below. 
- <https://developer.mozilla.org/en-US/docs/Web/CSS/animation> 
- <http://www.w3.org/TR/css3-transitions/#animatable-css> 
- <https://developer.mozilla.org/en-US/docs/Web/CSS/border-color> 
- <https://developer.mozilla.org/en-US/docs/Web/CSS/border-radius> 
- <https://developer.mozilla.org/en-US/docs/Web/CSS/border-width> 
- <https://docs.webplatform.org/wiki/css/properties/border-color>{.broken_link} 
- <https://docs.webplatform.org/wiki/css/properties/border-radius>{.broken_link} 
- <https://docs.webplatform.org/wiki/css/properties/border-width>{.broken_link}