What are the ::before and ::after pseudo-elements used for?
Jun 23, 2025 am 12:23 AM
The ::before and ::after pseudo-elements of CSS are used to insert decorative content or auxiliary layouts before and after element content. Common uses include: 1. Add decorative elements such as icons, separators, or custom bullets; 2. Insert context-related text or symbols such as external link logos or chapter numbers; 3. Clear floats to solve layout problems (old technology); 4. Implement silhouettes, borders and other style effects without adding HTML tags. Both can be styled independently and used in conjunction with positioning, but content added through the content property cannot be selected or accessed reliably on the screen reader and should not contain critical information.
The ::before and ::after pseudo-elements are used to insert content before or after the content of an element in CSS. They're commonly used for decorative elements, adding icons or text without changing HTML, or clearing floats.
Add Decorative Elements
These pseudo-elements are perfect for adding small visual enhancements like icons, background shapes, or separators. Since they don't require extra markup, you can keep your HTML clean while still achieving a pollished look.
For example:
- Adding quotation marks around a blockquote using
content: "“";inside::beforeand::after - Creating custom bullet points for lists
- Making toolstips or badges with small triangles using border tricks on
::before
They work best when you want something subtle that supports the design but isn't essential to the content itself.
Insert Contextual Text or Symbols
Sometimes you need to add small bits of text based on context — things like “(required)” after form labels or chapter numbers in a document layout. You can do this without touching the HTML by using ::before or ::after with the content property.
Some common uses:
- Showing external links with an icon or text like
(external) - Displaying dates or categories in blog posts dynamically
- Adding prefixes or suffixes conditionally based on classes
Just remember: content added this way is not selectable or accessible to screen readers reliable, so it shouldn't contain critical information.
Clear Floats (Older Layout Technique)
Before Flexbox and Grid, people often used ::after to clear floats. The trick was to apply something like:
.clearfix::after {
content: "";
display: table;
clear: both;
} Then applying the .clearfix class to any container with floating children would prevent layout issues. It's less needed now, but you might still see it in older codebases or CMS themes.
Style Without Extra Markup
One big benefit of ::before and ::after is that you can style them independently from the main element. This lets you layer effects like shadows, overlays, or borders without wrapping content in extra divs.
A few practical cases:
- Adding a line under headings with a bit of spacing using
::after - Creating double borders or multi-layer backgrounds
- Animating hover effects that come in from one side
You can even stack both ::before and ::after on the same element for more complex visuals.
Basically that's it. They're flexible tools once you get used to how they behave — especially with positioning and stacking.
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