Banners and block not loading on some browsers

[trico]

I'm running into an issue with my home page. The testimonials block (which I've renamed "Good to Know") and two main banners (graphical, one-by-one slider) aren't showing up on the main website page in some browsers. The testimonials/"good to know" block itself appears, but the content doesn't. (The content doesn't load on any page in the browsers - the block appears on all of the pages.)  The URL: --removed--

The AbanteCart cache has been cleared, and browsers have been checked with cache cleared.

It seem to work fine on:
PC: Edge, Firefox
Mac: Usually works in Chrome; does not load initially in Firefox, but will load after pressing "shift + r" a couple of times.

It doesn't work on:
PC: Internet Explorer 11, Chrome
Mac: Safari, Opera, Firefox (initially)

Browser versions were recent ones; I wasn't able to check various versions of each browser. I am running 1.2.8, upgraded from 1.2.7, upgraded from 1.2.6. The site has been in development through these upgrades, so I'm not sure if was an issue for earlier versions (I didn't check).

I'm not sure what to check or what I may have done, since it seems to work on a couple of browsers but not on others. Any ideas? I might just try to replace the main rotating banners with a static one, but it would be nice to have the rotating ones loading.

Thanks!

[Basara]

Any ideas?

Hello. I see your modify default template so maybe you change something important
Try to use firebug or browser inspector to debug errors. For example I see this error from time to time on your site "custom.js:26TypeError: process_thumbnails is not a function. (In 'process_thumbnails()', 'process_thumbnails' is undefined)"  As you can see something wrong with javascript

[trico]

Problem solved. I started to look at the errors in the inspector in Firefox, and then it occurred to me that I didn't update my template files in the extensions folder along with the rest of the site. So I did that for the style and javascript folders, and found a number of discrepancies - either updates not updated and/or errors on my part. I've brought the custom template files up to date, and that seems to have solved the problem.

Thanks for pointing me in the right direction!