onclick or onClick?

Question

I thought that binding the click event in javascript is done by using node.onclick, and Chrome/Firefox seem to agree with me, but I saw it written .onClick here 4 times by 3 people, so it can't be a typo and I doubt that it's a coincidence.

So, why are people writing onClick when it does not work?

UPDATE: There are two good explanations; I don't know which one of them is the most plausible, so I will accept the answer based on popular vote, tomorrow.

One more thing to add: if the old XHTML DOCTYPE is used, all attributes must be in lower case. — Raptor, Aug 26 '14 at 09:33

score 32 · Accepted Answer · answered Dec 07 '10 at 19:27

32

Because some browsers (depending on the DOCTYPE) are tolerant of the inline onClick="something();" attribute...it seems to have spread a bit, even into JavaScript questions where it doesn't work, since case matters.

Also, specifically to stackoverflow...people using it in questions...well, most of the time they wouldn't be asking a question if their code worked :)

answered Dec 07 '10 at 19:27

Nick Craver

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well I thought about that, but ... did it spread _that_ much? – Gabi Purcaru Dec 07 '10 at 19:28
@Gabi - yup, that's the best I can figure, based on all the questions I've seen it popup in, and the inline attributes used by the same users. – Nick Craver Dec 07 '10 at 19:30
There's also the equivalent method in ActionScript which people often have as `onClick` that causes further mutation. – Orbling Dec 07 '10 at 20:03

score 15 · Answer 2 · answered Dec 07 '10 at 19:35

@Nick Craver pretty much has it nailed down and has my vote; I just wanted to add my thought.

I think it's onClick is often used in conversation because it's a bit more readable, and as an old habit from those of us who predate all lowercase HTML. However, in code - both JavaScript and HTML, onclick is correct and the only way it should appear. Even if you're using an older HTML doctype, stick to lowercase. If you ever update to a more strict doctype, you'll be glad your code doesn't need to be checked for case.

Gopherkhan · Answer 3 · 2010-12-07T22:56:37.670

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It's just that for most browsers HTML attributes are case insensitive, but JS is case-sensitive. onClick will work in html, but if you're defining the handler in JS, you need to use the lowercased onclick.

edited Dec 07 '10 at 22:56

answered Dec 07 '10 at 19:30

Gopherkhan

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in XHTML, HTML attributes are case sensitive. Most browsers will understand and render it fine, but your code will fail validation. – Surreal Dreams Dec 07 '10 at 19:36
hmm. Lax browser handling must have been what I was reading. I just read something about this the other week. – Gopherkhan Dec 07 '10 at 22:55

score 1 · Answer 4 · answered Dec 07 '10 at 19:32

In that specific question, I used "onClick" as the original question had it in that vein and I try to change as little of the OPs code as possible to make a solution, so that they can see their mistake easily.

The camel case is invalid technically, though I like camel case in general. Frankly, it always annoys me when I see that method, as I think "Where's jQuery!".

It is heavily prevalent in the world, I see it all the time in source.

I edited my answer on the referenced question to fit, thanks for pointing it out.

Anyone like to explain the -1? – Orbling Dec 07 '10 at 21:01 — Orbling, Dec 07 '10 at 21:01

onclick or onClick?

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