Kind of sort of off topic but I had a very similar situation recently. User claiming my NT web app just "wasn't working." He listed off all the "things it wasn't doing." Turns out he was using Internet Explorer. Fired up Chrome and all was well.
In your case Mike, you know with reasonable certainty that the HTML, JS, and CSS should be good to go.
Maybe clear the browser's cache? I had to do that myself yesterday. (Thanks Bruce ;-) )
Try a different browser. Firefox perhaps.