Alt Text for Images
Alternative text provides a textual alternative to non-text content in web pages. We will be discussing alternative text for images only, though the principles can be applied to media, applets, or other non-text web content.
Alternative text serves several functions:
- It is read by screen readers in place of images allowing the content and function of the image to be accessible to those with visual or certain cognitive disabilities.
- It is displayed in place of the image in browsers if the image file is not loaded or when the user has chosen not to view images.
- It provides a semantic meaning and description to images which can be read by search engines or be used to later determine the content of the image from page context alone.
The key principle is that computers and screen readers cannot analyze an image and determine what the image presents. As developers, text must be provided to the user which presents the CONTENT and FUNCTION of the images within your web content.