[whatwg] [html5] attribute value whitespace handling

[fora at annevankesteren.nl]

Quoting Ian Hickson <ian at hixie.ch>:
>>  <input type="email" value="    example at example.org
>>     ">
>>
>> ... valid or invalid?
>
> The form control there would not be valid. There's nothing in either HTML4
> or WF2 that says that leading whitespace on the value="" attribute should
> de stripped, as far as I can tell.

They "may be stripped" and authors should not include them. Still 
confusing and
in need for clarification.

In two steps:
1. <http://www.w3.org/TR/html401/interact/forms.html#adef-value-INPUT>
2. <http://www.w3.org/TR/html401/types.html#type-cdata>