Simon:
I appreciate the clarification, makes me feel less apprehensive.
Anyone (rightfully) avoiding Chrome should at least look at Orion. It’s based on WebKit. Orion F.A.Q.
And, for the record, Jack in the Box website renders just fine. 
JackInTheBox.com renders just fine on Safari here, but that’s 16.3 running on Ventura 13.2.1.
Mmmh, cheeseburgers… 
It seemed OK for me too (Safari 16.3.1 on Bug Sur).
The site initially loaded with the same blank screen (with the small black squares in the upper-left corner), but after a second pause, everything else loaded. No change after a reload (CMD-R).
This seems like there may be scripting (possibly cross-site) involved, causing my delay. If @romad is running a content blocker that is preventing the scripts from running, that might explain why he’s not seeing the rest of the site.
I’m running AdblockPlus with the English-language Easylist filters. (Sadly, ABP isn’t nearly as configurable on Safari as it is on Firefox.) I have “Prevent cross-site tracking” enabled.
I did find that if I check the “Block all cookies” option, I get a blank page - not even the black squares or the “get free fries” button. So I ran a quick test. I went to Preferences → Privacy → Manage Website Data… I then removed everything and reloaded the Jack In The Box home page (and didn’t click on anything on the page) and went back to view the data. There were 15 sites present (!):
- attn.tv (cache)
- contentful.com (cache)
- cookielaw.org (cache)
- ctfassets.net (cache)
- fonts.googleapis.com (cache)
- google-analytics.com (cache)
- googletagmanager.com (cache)
- gstatic.com (cache)
- jackinthebox.com (cache, cookies, databases, local storage and HSTS policy)
- mparticle.com (cache)
- px-cloud.net (cahce)
- redditstatic.com (cache)
- sc-static.net (cache)
- snapchat.com (cache and local storage)
- tiktok.com (cache)
I’m guessing that @romad has a content blocker that is blocking all of this cross-site data, and that’s what’s breaking the site.
FWIW, I don’t have the same experience as you. Just the opposite, in fact. I find Safari compliance for nearly every site I visit, including many now that historically did not. And considering iPhone has nearly 30% of the smartphone market, and Safari is used on nearly all of those phones, it would be quite a surprise if web site developers ignored testing for Safari compliance as a matter of course.
Again, can only speak to my personal experience, but that site loaded immediately and completely for me. I’m on the latest Ventura/Safari versions, and I’m running 1Blocker in Safari.
I don’t understand either but I have had people at multiple sites tell me the site was only “guaranteed” to work w/Chrome. I’ve been asked what browser I used & when I’ve said Safari, I’ve been told that Safari wasn’t a browser that was considered compatible w/the site.
Often I’m told to use the company’s app instead of a browser on the site. Think lots of companies are assuming most people are using a mobile device, not a computer.
I don’t like relying on apps & mobile devices. I use my iPhone & iPad a lot but use my Mac even more. I have vision issues & find using apps much more difficult, prefer to use a browser.
Even on a mobile device, a site on a browser is often easier to see than an app.
My opinion, FWIW.
It’s just the opposite for me; I’ve had to use Safari much more in the past six months (because sites don’t work with Firefox) than before.
Same here. I wish I could disable Prevent cross-site tracking for specific sites only.
Yes, I had the AdBlock extensions for Safari running. I added the site to the allowed sites list and relaunched Safari. Launched the website but no joy. Next I unchecked the AdBlock extensions leaving only 1Password and tried again without success. I then went into Manage Website Data and deleted the site’s entry. Again closed Safari, relaunched Safari, reentered the website. This time I got this:
but nothing else.
Edit. OK I just went back into Preferences>Privacy and unchecked “Prevent cross-site tracking” Still no luck.
Edit Part Deux. This is not in Safari on my iPhone but rather in Safari 13.1.2 on my iMac. Maybe that is the problem. However I don’t have a problem with the site in Brave 1.48.164 or Firefox 102.8esr
It’s worth testing your browser in a different user account so all of the settings are the defaults. Go to system settings/preferences, and find Users and Groups. Authenticate as an admin user, and turn on the guest account, or create a new standard (non-admin) user. I turn on fast user switching too, so I don’t have to log out of my regular user. Switch to the guest user and try the sites you’re having trouble with. If they work, then the issue is with your regular user account and that limits the things to try.
In your regular account you can also delete all cookies, caches, and databases, though that will delete all site settings. You can do that with safari preferences in the privacy tab. Remove everything, then wait awhile and if the list repopulates, remove all again, then keep waiting. Sometimes it takes several tries to clobber things completely.
I’m still using Safari on Sierra for many things, and I get quirks and failures that I don’t get on a test user or on my El Capitan system due to some corruption in the settings that I haven’t bothered to fix yet. On my Catalina mac, I get different quirks and failures, including unresponsive links and form fields, but that seems to be because more sites are requiring you to use new versions of browsers, mostly to support newfangled and usually irritating features but partly to improve security. I suspect that some failures are due to my slow network connection as those irritating newfangled features stumble over each other.