- Build some webapp and get it working correctly in Chrome
- Test on Firefox. It works 90% of the time. 9% of the time it's relatively easy to support. 1% of the time it isn't worth the hassle.
- Test on Edge. It works 80% of the time. 10% it's an easy enough fix. 10% you have to move heaven and Earth to fix and when you contact Microsoft, they know about the issue but won't do anything to help.
- Test on IE. It works 60% of the time. The other 40% of the time you start looking for a new job so you don't have to write the same code a second time for IE.
Fun, now a few rare numbers on one of our sites seem phone number enough for the dutch locale to break the site. Tell the user to switch to the french locale as workaround, or get any other browser. MS wants you to change the html to say: hey edge, this is not a phoneable number.
WTF, microsoft? Way to shoot yourself in the foot. What else did you hide in there that will bite me one day?
We rewrote the app so it didn't use ClickOnce in the end.