I am working on a project for a client who wants to transition content within an iFrame in a prescribed order. Most of the JavaScript snippets I've found were for image or text transitions, but nothing that would replace the source of an iframe. Additional detail can be found below:

array=
page1.html
page2.html
page3.html

<!-- Start the iframe with the page1.html -->
<!-- Swap the HTML page every 15 seconds -->
<iframe src="page1.html" ...></iframe>
<!-- END -->