How to show an alert (or hidden div) when selecting a particular option in a select element

How to show an alert (or hidden div) when selecting a particular option in a select element

This is probably a simple question, but I'm not sure how to do it.

I'd like to have an alert of some type, either standard alert or a hidden div, show up when a user selects an option in a select element.

For instance, if a select element has 5 options in it and the user chooses the first one, they would get an alert that says "You have chosen the first option". I'm confident this is something that can be done with a few lines of code, but I'm not sure where to begin.

Here's the logic - I'm just not sure how to write the syntax...

If ("#select option") changes and ("#select option:eq(0):selected"), fade in the div ("alert").

Anyone have any suggestions? Thanks much, Marcus.