Pop up image on click of a box
I've got a form on a webpage which will have 'does this relate to an ICT suite?'
On ticking this box, another select box will appear and list the different suites.
What I'd like to do is then have another select box appear with the listed computers in that suite, and also have an image of the room layout displayed in a 'greybox' type manner with each computer marked on it and then when they click on one, it selects it in the select item (it'd be a multiple select item, so multiple ones would need to be clickable).
Does anyone have an idea how to do this? The problematic part here would be the floating 'on top' window.