Scripsit Paolo:

>> @media screen { .print-only { display: none; } }
>>
>> Problem solved?
>
> NO!

You didn't apply the advice properly.

To get more specific information, enter more specific information of
what you tried. This means telling us the URL.

It's generally counter-productive to spot people's errors unless they
show us the URL. Sometimes it is possible, but it will teach them (and
others) bad habits. So is it immoral for me continue before we have the
URL? Maybe, but I feel a bit bad guy today...

> I try to apply that you wrote but the result is to hide the content
> of the second <td> and not only the <td> tag

What? Are you really trying to hide _tags_ and not elements? (The
confusion is common, but it was already correct in this thread. Please
stand corrected until you understand the point.) And what is "the second
<td>" as opposite to "the <td>tag"?

> I'ld wanted to display my tables into a single column on screen and
> into two columns printing the page to have printed one page only.

Sounds strange. I wonder what the real use case is.

> I wrote here a little sample

URL, please.

> <style>

Use valid markup. Moreover, close all table-related elements with
exlplicit end tags to avoid browser bugs.

--
Jukka K. Korpela ("Yucca")
http://www.cs.tut.fi/~jkorpela/