What is the purpose of the content property in pseudo-elements?
Jul 13, 2025 am 02:50 AM
The content attribute is used in CSS to insert generated content into a pseudo-element. Its core role is to add visual content in non-HTML structures, such as text, symbols, pictures, or automatic counters. 1. Insert text or symbols: can be used to add labels or icons, such as "Note:" or Unicode characters; 2. Add images or counters: supports inserting pictures and implementing automatic numbering; 3. Style control: styles such as fonts, colors and layouts can be applied to the generated content; 4. Use restrictions: It should be avoided to use critical information or large amounts of text to avoid affecting accessibility and maintenance.
The content property in CSS is essential when working with pseudo-elements like ::before and ::after . Its main purpose is to insert generated content into the document tree—content that isn't present in the actual HTML markup but appears visually on the page.
Why Use content with Pseudo-Elements?
Pseudo-elements like ::before and ::after don't do much on their own. If you try to style them without using the content property, they won't show up at all. That's because browsers ignore pseudo-elements unless there's something to display. The content property gives you a way to define what that "something" is.
Inserting Text or Symbols
One of the most common uses of content is inserting text or special characters before or after an element. This can be helpful for adding labels, icons, or decorative elements without modifying the HTML.
For example:
p::before {
content: "Note: ";
font-weight: bold;
}This adds the word “Note: ” in bold at the beginning of every paragraph. You could use this to highlight warnings, tips, or other recurring messages.
You can also use Unicode characters or emojis:
li::before {
content: "\2713"; /* Unicode checkmark */
margin-right: 5px;
}Just keep in mind:
- The inserted content is not selectable or searchable by users.
- It should not be used for important information that affects accessibility or SEO.
Adding Images or Counters
Besides text, you can use content to insert images or create automatic counters.
To insert an image:
div.banner::after {
content: url("icon-star.png");
} This places an image next to the banner without needing an <img alt="What is the purpose of the content property in pseudo-elements?" > tag. It's useful for small icons or decorative graphics.
For counters:
body {
counter-reset: section;
}
h2::before {
counter-increment: section;
content: "Section " counter(section) ": ";
}Now each heading will automatically be numbered as "Section 1", "Section 2", etc. This is great for documentation or long-form content where you want to organize sections dynamically.
Styling Generated Content
Once you've added content via content , you can style it just like any other element. You can apply margins, colors, fonts, and even positioning.
For example:
blockquote::before {
content: open-quote;
font-size: 2em;
color: gray;
}This adds a styled quotation mark before every blockquote. Common values include:
-
open-quote/close-quote -
"string" -
url(image.jpg) -
counter(name)
You can also set properties like display , position , or float to control how the generated content behaves visually.
When Not to Use It
While content is powerful, it's best used sparingly. Avoid inserting large chunks of text or anything that conveys critical meaning, since screen readers may not interpret it consistently. Also, overusing pseudo-elements can make styles harder to maintain.
In short, think of content as a tool for visual enhancements rather than structural content.
Basically that's it.
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