DHTML pop up on Html site

Want to add a DHTML pop up to an existing website which is in standard HTML. The pop up should work on [login to view URL] the same way it pops up on [login to view URL] Not sure if it is possible or how it works hence why had to come here. Because many sites have this kind of pop up. The pop up should be able to capture name and email as well as advertise a product (just like the one on the site given as an example). Please if you cannot do the job or do not know the job do not bid-- Please now!