Best way to Update row...

[Anon]

from a user submitted form I have the following scenario:

a select drop down with a variable assigned $item1

an input box with the variable $item2

I have javascript in place that checks to make sure that one or the other is filled out, NOT both.

On the update page... what would be the best way to rename whichever selection they make to a variable that gets inserted into the database?

I have a feeling it would be an if statement, just not sure on the logic to use..

[Anon]

if (isset($item1)) {
$new_var = $item1;
} else {
$new_var = $item2;
}