I would create a <div> on your page that contains the HTML, graphics, content, links, etc.
In your CSS stylesheet, you start out with that <div> hidden.
display:none; keeps it hidden from view.
In your page you have:
Visit today for specials on blah blah blah.
Then you put this on the top of your page (in the <head> section) so that <div> appears when the page loads.
Put that .js file in the same directory as your page (or wherever you decide).
Using JQuery allows you to do many things, such as fade the <div> into view,
fade it back out, etc.