They may appear in any order.
Attribute names are always case-insensitive.
Attribute values are generally case-insensitive. No mention is made what should happen if data is submitted that is NOT from any of these sets. If this attribute is absent it defaults to the BASE URL of the current document. A value of 'Yes' indicates Autocomplete is enabled, and 'No' disables. In the POST method, the contents of the form are encoded exactly as with the GET method, but the contents are sent in environment variables in the HTTP transaction.