What happens if allowfullscreen is not supported by a browser?

Answers:

• If the allowfullscreen attribute is not supported by a browser, the behavior of fullscreen functionality will be determined by the specific browser's implementation and the way the HTML5 <iframe> or <video> elements are handled. Here are a few possible outcomes:

  1. No Fullscreen Option: If fullscreen support is not available, the fullscreen button (if present) may simply be disabled or not appear at all. The user will not have the option to enter fullscreen mode for that video or iframe.

  2. Fallback Behavior: In some cases, the content may still play but without the ability to view it in fullscreen. Users would need to view it within the confines of the default player or iframe dimensions.

  3. Browser-Specific Behavior: Different browsers might react differently. Some older browsers or specific versions might ignore the allowfullscreen attribute altogether, while others may simply not implement fullscreen functionality.

  4. Developer Handling: As a developer, you can implement JavaScript or CSS to check for fullscreen support and provide alternative layouts or messages for users on unsupported browsers.

  To summarize, if a browser doesn't support allowfullscreen, users won't have the ability to view content in fullscreen, and depending on the browser, the experience may be downgraded without any explicit notification to the user.

Related Questions:

• What is the purpose of the allowfullscreen attribute?
• What are the security implications of using allowfullscreen?
• How can I check if allowfullscreen is supported in a browser?
• What browsers currently support allowfullscreen?
• Can I force fullscreen mode without allowfullscreen?