On 2008-03-02, Mike Barnard <m.barnard.trousers@thunderin.co.uk> wrote:
> Hi.
>
> In a site I have set the height of a footer div to 4em. This doesn't
> validate, therefore I *assume* that em is not a valid value. I will
> change it, of course, but I want to learn the correct possible values.
>
> Sorry! We found the following errors
> URI : http://www.thermachek.com/temp/thermachekv2.css
> 181 #footer Value Error : height Parse Error - 4em

You forgot the :. You wrote 'height 4em', not 'height: 4em'.

> OK, so I went to http://www.w3schools.com/css/css_reference.asp to
> read up. Under height is says the possible values are auto, length or
> %.
>
> So whats the definition of 'length'? Searching the site has brought up
> nothing, so far. It must be there, but I can't find it. Can anyone
> point out the px in what % of the site for em?

An em is a perfectly good length unit, you jumped the wrong way.

Validators etc. can give slightly misleading error messages because
after all they're only non-human.

The main useful information is just "there's something wrong near line
181". Everything else take with a pinch of salt.