They may appear in any order.
Attribute names are always case-insensitive.
Attribute values are generally case-insensitive. A single character is used as the value of this attribute. A single, case-insensitive alphanumeric character from a browser's character set. A value of 'Yes' indicates Autocomplete is enabled, and 'No' disables. This is a stand-alone attribute which tells the browser that content in the field may not be modified by the reader.