> why should there be performance idiosyncrasy among browsers?
Because the engines work differently, some are better at some parts and worse at others. That's just the name of the game when you have different implementations of something.
Not saying that work shouldn't be done do make them on-par with each other, just providing a reasoning why things are like they are. I remember at one point some Google product was using some JavaScript API for lots of things and obviously only tested things in Chrome, when testing it in Firefox the performance was a lot worse, as Gecko performed worse than V8 using the data structure/API. They ended up disabling Firefox access to it because of this.
Eventually, Firefox got the bug fixed I think, so the product enabled support for Firefox.
I guess the point is, the standards around the web platform say how the user should be able to use some API/format/structure, not much about how said API/format/structure is internally implemented.
Because the engines work differently, some are better at some parts and worse at others. That's just the name of the game when you have different implementations of something.
Not saying that work shouldn't be done do make them on-par with each other, just providing a reasoning why things are like they are. I remember at one point some Google product was using some JavaScript API for lots of things and obviously only tested things in Chrome, when testing it in Firefox the performance was a lot worse, as Gecko performed worse than V8 using the data structure/API. They ended up disabling Firefox access to it because of this.
Eventually, Firefox got the bug fixed I think, so the product enabled support for Firefox.
I guess the point is, the standards around the web platform say how the user should be able to use some API/format/structure, not much about how said API/format/structure is internally implemented.