Embeddable Popup Widget for Websites and WP

I need a javascript embed code that will create a popup image with link on either a website or wp site. The image and link information should be available on a server that will serve the information and create the code snipet for the user to place on their website. The script should use php to create the script. Something similar to a form embed code like this: <div class="display"></div><script src="URL/f/[login to view URL]" type="text/javascript" charset="utf-8"></script> The settings on the popup would be controlled in the script. Height, width, position, link, image, etc. Example, on my site, a user would be able to identify all of the variables above, and the script would create the embed code to be inserted by the user onto their own site. This is common practice in email providers to embed forms on sites. Same idea. Please message me with questions.