What is the :visited pseudo-class used for in CSS?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of HTML & CSS conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
The :visited pseudo-class styles anchor links (<a>) that the user has already navigated to in their browser history:
a:visited {
color: #7c3aed; /* Purple indicator for visited links */
}
### Strict Browser Privacy Restrictions:
To prevent malicious websites from sniffing a user's browsing history by styling links and reading back computed styles with JavaScript, modern browsers enforce strict security restrictions on :visited:
- Only color-related properties are permitted:
color,background-color,border-color,outline-color, and SVGfill/stroke. - Alpha transparency components are ignored.
- JavaScript methods like
getComputedStyle()will always lie and report the unvisited color.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.