Add allow="web-share" to Spaces iframe for Web Share API support

[SyntaxSphinx]

Is your feature request related to a problem? Please describe.

when running a Streamlit/Gradio Space on huggingface.co/spaces/*, the Web Share API (navigator.share()) throws NotAllowedError: Permission denied. This happens because modern browsers (Chrome 110+, Safari, Firefox) block the Web Share API in third-party iframes unless the parent page explicitly allows it.

Describe the solution you'd like
Add allow="web-share" to the iframe element that embeds Spaces on the huggingface.co/spaces/* pages:

<iframe src="https://user-space.hf.space" allow="web-share" ...>

Describe alternatives you've considered

• Download-only flow (current workaround) - works but less convenient for mobile users
• Opening the Space in a new tab at the direct .hf.space URL - confusing UX
• Storing images server-side and sharing links - adds complexity and storage costs

Additional context

• Chrome requirement: https://developer.chrome.com/blog/web-share-api-in-third-party-iframes
• Safari/WebKit: https://webkit.org/blog/13708/allowing-web-share-on-third-party-sites/

My Space (Itivrit AI) generates shareable image cards that users want to share directly to WhatsApp, Instagram, X, etc. This feature would benefit any Space that generates downloadable/shareable content.

[julien-c]

maybe @cbensimon

[stephenmyers360-cpu]

could we possibly write it using python coding since it is one of the most recognizable formats on most sites ?

[julien-c]

Thanks for the suggestion @stephenmyers360-cpu! Unfortunately this isn't something that can be solved with Python code on the Space side. The issue is that the browser blocks the Web Share API inside iframes unless the parent page (huggingface.co) explicitly adds allow="web-share" to the <iframe> HTML tag. That's a platform-level change that needs to happen on the HF website itself, outside of any individual Space's code.