AMP will start supporting forms - see #3343, filing this to get discussion going and to start on the validator part in parallel.

• Allow usage of form, input, textarea, select, option tags in AMP Docs.
• Must include amp-form extension script if document uses form/input/select/textarea tags.
• Must use inputs tags inside form tag.
• Form must have at least one <input type=submit>
• Form must have action=”absolute non-cdn https url”
• Form must have target=”_top|_blank”
• <input type=”file|password|image|button”> are invalid
  • This might be revised later on.
• Other than normal form attributes, allowed attributes include:
  • action-xhr - Optional - to enable a submission flow through XHR. Also has same validation as action attr (absolute, non-cdn link and https) except not required.

cc/ @powdercloud @Gregable @rudygalfi