Opera & Nulls

[lead2gold]

why does every browser except opera treat <div class="classname"></div> as absolutly nothing (or dependant on the actual class attributes).

Where as Opera puts the keyword "null" on the page as place holder.

It's much cleaner and easier to code stuff like this:
[code]
<div class="dberror"><?=$error; ?></div>
[/code]

instead of
[code]
<?=($error)?"<div class=\"dberror\">$error</div>";
[/code]


The cleaner approach works in every browser except opera :( *sniffs*
How do you guys do it?