onMouseDown event? + Capture mouse location while click&drag?

Hello,

I'm new to Photoshop plug ins. Actually, I'm still elaborating
if I will be able to write a plug in from what I intend to do.

I have the following question:
In JavaScript I can capture a onMouseDown event and I can
also capture the mouse location (?) while I click&drag
within a rectangle (div..).

Is this possible in a photoshop plugin?

Thank You, John