What is "javascript:" used for, and is it compliant?

Question

What is javascript: used for, and is it compliant and should I use it?

I noticed that some of my associates choose to use

javascript:

followed by some function name or some JavaScript code, but it seems unnecessary to me.

I see this a lot in event handlers like:

onclick="javascript: somefunction451();"

Also I have trouble searching for more information on javascript: because it says that I'm trying to do cross site scripting. Especially if I stick it in quotes. Is this something that simply can't be fixed? Should I search this in a Flash only or Silverlight only browser?

possible duplicate of [onclick="javascript:func()" vs. onclick="func()"](http://stackoverflow.com/questions/10242576/onclick-javascriptfunc-vs-onclick-func) — , Jun 07 '12 at 14:34
am not i am: Thanks for the link. Now the only question I have is why is it so difficult to do a search on javascript: in a browser? — RetroCoder, Jun 07 '12 at 14:42
Google strips out characters like ":" in a search. Instead try "javascript followed by a colon". — Jonathan M, Jun 07 '12 at 14:45

score 7 · Accepted Answer · edited Jun 07 '12 at 14:42

7

It's completely unnecessary in "onfoo" attribute values. In that context, it's interpreted as a label by the JavaScript parser. Thus it's not erroneous, but it's useless.

In "href" values, it has a role, but there's really no reason for JavaScript "href" values anyway.

edited Jun 07 '12 at 14:42

Quentin

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answered Jun 07 '12 at 14:30

Pointy

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I agree that there is no need for JavaScript "href" values. You see a lot of `` that could just be a ``. I find it very annoying when I hover a link and I see "javascript:void(0)" in the corner of my browser. – lbstr Jun 07 '12 at 16:48
Well one reason to use `` instead of `` is that it's better for keyboard-based navigation. An href of "#" is probably better than the "javascript:void(0)" I think. – Pointy Jun 07 '12 at 16:52
You can throw a `tabindex="0"` on a span and then you can tab to it like you normally would with form elements, anchors, etc. I'm no expert on screen readers though, so you may be right that anchors are a better choice in that regard. As far as `href="#"` goes, I have one reservation: the page will scroll to the top on click. If your app isn't any taller than the window height, this is fine. Let me know if there is a way around that. – lbstr Jun 07 '12 at 17:14
@lbstr yes true, but the event handler can disable the default action to avoid the scrolling. – Pointy Jun 07 '12 at 17:17
Ahh I didn't know that preventDefault() would disable that. Another approach that I just noticed on this very page is an anchor with no `href` attribute at all. Maybe thats the winner?? No browser displaying # or javascript:void(0) on hover. No need for extra js to prevent scrolling. Keeps good semantics by using the `a` tag instead of `span` or `div`. – lbstr Jun 07 '12 at 17:27

score 1 · Answer 2 · answered Jun 07 '12 at 14:40

1

It's "unofficial" but "common" and "works in any modern browser" in the place of a URI scheme name per this source: http://en.wikipedia.org/wiki/URI_scheme

This would apply then to <a href="javascript:... only. It's necessary there (but there are better ways to invoke javascript when clicking on an element).

In the onClick= attribute and such, it is a label and unnecessary.

answered Jun 07 '12 at 14:40

Jonathan M

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Thanks for the URI_scheme. I had no idea it was that complex. – RetroCoder Jun 11 '12 at 17:02

What is "javascript:" used for, and is it compliant?

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