Centrally Updating All Banners and Links

I have pretty much no knowledge in coding but pick up what I need along the way. I use a visual site designer to build my website, and am currently building a site with around 80-90 pages with affiliate links and banners that are repeated on almost all the pages.

Commission Junction provides banners/links in both HTML and Javascript

The javascript code for a banner looks like <script type="text/javascript" language="javascript" src="http://www.abcdefg.com/placeholder-1234567?target=_top&mouseover=N"></script>

whereas the HTML version looks like <a href="http://www.abcde.com/click-1234567-12345678" target="_top">text</a><img src="http://www.mnopq.com/image-1234567-12345678" width="1" height="1" border="0"/>

Is there any way I can use an external Javascript file and either of the above two formats so that I can easily update the same banner/link on all my webpages by simply modifying one file or location?

Would really appreciate help and a 'step-by-step' answer as to how to implement this.

I have pretty much no knowledge in coding but pick up what I need along the way.
The best advise I could give you at this point is "Stop!". Go study coding. http://www.w3schools.com/
What your asking is basic and definitely needed for a 80-90 page site that your just going to be coming back here asking question all the time. Study, learn; You'll be happier and things will go faster for you.

Loading a header into a div with a require('./header.html'); is also used for the footer and nav column in most cases.