[thelist] CSS Question

[Salvatore Palmisano]

Ive seen this a few times recently:

WIDTH: 100px;
WIDTH: expression(200);

What does the second WIDTH do?  'Expression' looks like a function call with
a 200 variable; is that another way of spacing 200px?  Why do both?

I did a search at MSDN, Google/Dogpile and a few other CSS references and
was only able to find WIDTH references, not the expression call.
Thanks all.

--Salvatore