if (el.classList)
el.classList.contains(className);
else
new RegExp('(^| )' + className + '( |$)', 'gi').test(el.className);
$(el).hasClass(className);
The point is that this site explains how you do it because a) that's probably easier than trawling through the jquery source b) including this polyfill when you know you need it might save you from requiring all the rest of jquery.
Yes use jQuery if it's really providing benefit, but if you're only using it for a few things, you may be better off just doing in in plain javascript, even if it's a bit longer.
Every library you add has an overhead cost on the end user as they have to fetch it and process it. It's easy to lose track of that when you're developing and testing against local webservers or on computers vs mobile, but there is strong value in keeping things small and with as few unnecessary dependencies as possible :)
This is as ridiculous as having a "addition" module in jQuery and saying that people who do addition in JavaScript are just reinventing jQuery.
Wrapping jQuery around something simple (like fading in) does not make it into jQuery. If anything this just demonstrates who incredibly unknowledgeable people are about where jQuery ends and JavaScript begins.
printf is a part of the standard C library.
As soon as you do that though (put the two on equal-ish grounds), you realize it doesn't make much sense and it might as well not have been written in the first place.
On the other hand, I've seen actual backlash against printf implementations in libs and the bloat they're causing, never mind potential bugs [1].
So there you go.
jQuery's ratio of size-versus-additional-utility is much larger than printf's, even more so if you consider typical use cases of each.
But it isn't even a fair comparison to begin with. How about comparing jQuery to libc. I'd still argue the ratio is in libc's favor, but no one would have written "I'm surprised that there's no youmightnotneedlibc.com".
I still wouldn't be so sure about that ratio. The people decrying the printf family of functions are often targeting small statically linked binaries. Where a few kb shaved off might be a bigger chunk than 30kb are for your usual multi-megabyte front page of today's web.