Definition
Alt Text (Alternative Text) is a brief description added to an image tag in HTML to describe the appearance and function of an image on a webpage. It serves several critical purposes, including improving web accessibility for visually impaired users who rely on screen readers to interpret and navigate web content. Additionally, alt text can enhance SEO by providing search engines with context about the images, aiding in their indexing and understanding of the page content.
Importance in Web Accessibility and SEO
- Web Accessibility: Alt text enables visually impaired users to understand images, contributing to a more inclusive internet.
- SEO Benefits: Provides search engines with context, helping them index images correctly, which can lead to better visibility in image search results.
Types of Alt Text
- Descriptive Alt Text: Offers a concise description of the image’s appearance and relevance to the content.
- Example: “Golden retriever playing fetch in a sunny park.”
- Functional Alt Text: Describes what the image does, especially if it’s a button or a link.
- Example: “Submit button for contact form.”
- Decorative Alt Text: For images that are purely decorative and add no informational value, it’s best to use an empty alt attribute (alt=””) to indicate that they can be ignored by screen readers.
- Example: An ornamental border image would have alt=””.
How to Write Effective Alt Text
- Be Concise: Aim for a succinct description that captures the essence of the image without being overly detailed.
- Include Keywords: Incorporate relevant keywords to improve SEO, but avoid keyword stuffing.
- Avoid Redundant Phrases: Skip phrases like “image of” or “picture of,” as screen readers already announce images as such.
- Describe the Important Elements: Focus on details that are relevant to the content and the context in which the image is used.
Examples
- For an e-commerce site: “Black leather office chair with adjustable armrests and lumbar support.”
- For a travel blog: “Sunset view from Mount Everest Base Camp, highlighting the orange hues on the snowy peaks.”
Conclusion
Alt text is a fundamental component of web design and SEO strategy, enhancing web accessibility and search engine visibility. By providing a textual alternative to images, websites can ensure a better user experience for all visitors, including those using assistive technologies, and can improve their performance in search results.