[NEED] pop under script

OK coders...

I think that a javascript in the header could load a pop under whenever someone visits my page, correct? Example would be a product matching the theme of my page. My guess is it would be a simple line or two of code, but I know minimal coding. Any help?

I just created the first Ajax, lightbox popup that I am about to launch to the public in a week. It is super easy to install and I have a wordpress and PHP version of the plugin. You can set it to different pages and tell the JS when to call the the popup and customize the popup to whatever you like. I did build some templates that one could use. PM if you want to try it out. I am going to give BHW members a 50% discount at $19 for the popup in a about a week. I iwill have review copies available.