As I hinted to in the previous installment of this series; a radio button is in the same situation as checkboxes on the web: no options for styling the native component, but the same strategy we used for checkboxes can be applied to radio buttons as well.
The goals
- Style the radio button
- Style the label
- Require no additional DOM nodes or configuration (including icons/images)
- Require 0 JavaScript
The results
The strategy
- Hide the actual radio input
- Show a styled element that looks like an empty radio button when the input is unchecked
- Show a styled element that looks like a selected radio button when the input is checked
How to get there
The CSS selectors used
Type selector
type
- selects all elements of the giventype
(e.g.input
will select all<input ... />
nodes)Attribute selector
[attribute="value"]
- selects an element withattribute
where its value is exactlyvalue
Psuedo-class
:checked
- selects checkbox/radio input types oroption
s in aselect
that are selected/checked/on/activePsuedo-element
::before
- styleable element that doesn't actually exist in the DOM; considered the first child of the selected elementUniversal selector
*
- selects anything/everythingChild combinator
>
- combines two selectors; narrowing the selection on the right-hand side to only those elements that are direct descendants of elements selected by the left-hand side.Adjacent sibling combinator
+
- combines two selectors; narrowing the selection on the right-hand side to only those elements that are the siblings immediately after the elements on the left-hand side
Important CSS styles used
content
- used in the::before
psuedo-element to set its contentdisplay
- specificallynone
to hide elements andinline-block
to make our otherwise inline radio button able to have a consistent width and heightwidth
/height
- does what you think: sets width and height of the elementcolor
- sets the color of the texttext-align
/vertical-align
- used for adjusting the position of our radio button to its labelborder
styles - How we'll form and color the radio buttonradial-gradient
- used inbackground
to fill in the radio button in the classic "half-full" style
Starting out: the HTML
Let's set up our radio button as a child of its label
element with a sibling of a span
of the label text:
<label>
<input type="radio" name="key" value="value" checked />
<span>I am a radio button</span>
</label>
<label>
<input type="radio" name="key" value="another-value" />
<span>I am another radio button</span>
</label>
This structure allows clicking on the label text to select the radio without needing for
or unique id
attributes (Note it's important the name
is the same for at least 2 or more radio buttons. This creates the "radio group".). Placing the text in a span
directly after the input
will allow us to select it in CSS.
First step: hide the unstyleable radio
Going back to our strategy: since we can't do anything with the native radio button, we'll have to hide it and do our own thing.
label > input[type="radio"] {
display: none;
}
We'll select the radio button (input[type="radio"]
) and make sure it's labelled the way we need it to be (label >
). Then just display: none
to get it off our screens.
Second step: make our own radio button
Making an empty circle is easy with CSS, just put a border around a square element and give it a border radius of 50%
. As with the checkbox, we'll put this on the ::before
psuedo-element to avoid extra markup.
label > input[type="radio"] + *::before {
content: "";
display: inline-block;
vertical-align: bottom;
width: 1rem;
height: 1rem;
margin-right: 0.3rem;
border-radius: 50%;
border-style: solid;
border-width: 0.1rem;
border-color: gray;
}
Last step: make our radio change when checked
Again like the checkbox, using :checked
we can style our radio button to make it appear different when selected.
label > input[type="radio"]:checked + *::before {
background: radial-gradient(teal 0%, teal 40%, transparent 50%, transparent);
border-color: teal;
}
label > input[type="radio"]:checked + * {
color: teal;
}
The main difference between the radio button and the checkbox is the content and background. Here we have no difference in content and instead use a radial-gradient
to fill only a portion of the circle in.
Going more in depth on the radial-gradient
:
- We start with
teal 0%
, sinceradial-gradient
is defined from the center outward, we've basically said the center should start with teal. - Next
teal 40%
means "40% of the way to the edge should be teal". Since we started with teal,radial-gradient
makes a gradient from teal to teal, also known as solid teal. - Then
transparent 50%
will cause a blending from teal to transparent between the 40 and 50 percent marks. - And the final
transparent
results in solid transparency until the edge.
Putting all that together, we've essentially made a solid teal dot occupying 40% of its element (with 5% of gentle fading away on each side).
Wrapping up and side notes
Thanks for reading! I like sharing and finding things like this where common web design patterns can be done without a massive JavaScript library or framework bogging the page down. Give me some suggestions below on patterns you'd like to see me break-down in CSS/HTML-only for this series.
Follow me for the next installment in this series: accordians!
While this example had "no unnecessary DOM"; it is also perfectly valid to include an additional span
(or two) to hold svg/font-awesome icons for more precise/exotic radio button designs. Then :checked
should be used to alternatively display: none
and display: inline-block
the icons and +
will need to become ~
to select all the siblings.
Top comments (2)
when you hide the input using
display: none;
, you remove it from screen readers and keyboard users too. A better approach would be to use absolute positioning (on a positioned parent) and give it an opacity of 0. You should also try to give it the same dimensions as your new styled radio so that it correlates correctly when blind people are using touch discovery on a mobile device.I'd change to input like this:
input {
top: 0;
left: 0;
width: 100%;
cursor: inherit;
height: 100%;
margin: 0;
opacity: 0;
padding: 0;
z-index: 1;
position: absolute;
}