This is more common than you think. It's usually not broken entirely, but firefox constantly breaks styling/css stuff on websites I use and build. I've had a few sites ask me to switch browsers because firefox doesn't support x y or z feature too
Because in web development there are compatibility tables of what features work with which browser. If a developer has used a feature poorly supported, they either haven't done their homework, or intentionally made that call.
In web development, most reputable Front End Devs would not choose bleeding edge, barely supported features even if the temptation was there because the user comes first. Generally, you wait until it has been adopted by the main browsers (chrome, safari, ff).
Frankly, if something doesn't work in Firefox, thats like <5% market share. Probably lower for a lot of segments. I am familiar with webdev :) Let's not pretend most devs are checking caniuse for everything. Some sites leverage bleeding edge stuff that necessarily requires chrome, which is also fine. IRL people don't optimize for Firefox and that's usually okay, but sometimes there are quirks. That's all I'm saying
Not perfectly optimised is fine, but non-functional isn't acceptable. I've never seen a quirk personally, and quirks aren't a good reason to help maintain Google's monopoly on web standards.
You may say less than 5% is fine, but it could be the margins in a low margin industry. 2% could be 40% of the profit.
I haven't seen a team operate where a senior isn't checking it.
Usually the bleeding edge stuff is used by small companies trying to establish themselves because they have nothing to lose and no reputation to protect.
Plus, when you got Browser Stack, you catch a lot of problems like this.
Because is your product and you want to "sell" it to the "customer". And you can't blame the customer for not wearing the "correct dress" if they come to your shop. And if you don't want them in your shop it's your loss, not the customers'.
I remember trying to style a range input slider a few years ago and it worked everywhere except firefox. I also had problems with the style of the <select> recently (inverted colors, wrong font). Not a big deal, I still drive firefox daily, but there are idiosyncrasies
Discrepancies between the two systems doesn't mean there necessarily is a certain number of websites that the average user wouldnt be able to use in Firefox.
You are talking from the creator viewpoint not the end user, thats way different.
All true! I suppose I replied to a comment saying sites were nonfunctional, but that's more extreme than what I mean. The only nonfunctional sites Ive read about are from hackernews threads talking about WebGPU.