Numeric ID

The w3C validator says that a numeric ID, such as:
<div id="1">
(or an ID beginning with a number) is invalid: "It is possible that you
violated the naming convention for this attribute. For example, id and
name attributes must begin with a letter, not a digit."


But I can't seem to find anything that says you can't use a numeric ID -
I'll grant that I'm not a master at reading the specs, but all I CAN
find is that an ID should be unique, and should not use character
encoding. Maybe I'm just not seeing it:
http://www.w3.org/TR/REC-html40/struct/links.html#h-12.2.1
http://www.w3.org/TR/REC-html40/struct/links.html#h-12.2.3
http://www.w3.org/TR/REC-html40/struct/global.html#h-7.5.2

So - what about numeric ID's like above? Is it valid? And assuming it's
not, what sort of problems, aside from validation errors, would it cause?

Tony wrote:
> The w3C validator says that a numeric ID, such as:
> <div id="1">
> (or an ID beginning with a number) is invalid: "It is possible that you
> violated the naming convention for this attribute. For example, id and
> name attributes must begin with a letter, not a digit."
>
>
> But I can't seem to find anything that says you can't use a numeric ID -
> I'll grant that I'm not a master at reading the specs, but all I CAN
> find is that an ID should be unique, and should not use character
> encoding. Maybe I'm just not seeing it:
> http://www.w3.org/TR/REC-html40/struct/links.html#h-12.2.1
> http://www.w3.org/TR/REC-html40/struct/links.html#h-12.2.3
> http://www.w3.org/TR/REC-html40/struct/global.html#h-7.5.2
>
> So - what about numeric ID's like above? Is it valid? And assuming it's
> not, what sort of problems, aside from validation errors, would it cause?

They're not valid. Refer to:


http://www.w3.org/TR/REC-html40/types.html#type-name