Loading external local HTML file with HTML5 Preview

Hello!

I'm playing around with javascript on Captivate. What I'm trying to achieve is when a user clicks a button, a javascript will cause it to create a new window and then load a local HTML5 in that window. So far I've only been successful with opening a new window. I need help on where to put the HTML file since the preview of the course is on a local server indicated here: http://localhost:58365/preview/HTML5Temp23924693827609Pre/index.html 

I'm trying to figure out which folder to put that said file.

Any help is appreciated. Thanks!