[ACCEPTED]-When do I need to specify the JavaScript protocol?-correctness

Accepted answer
Score: 16

The javascript: pseudo-protocol on event handlers will 7 be only ignored, you don't need it, the 6 JavaScript engine will interpret javascript: as a Label Statement.

A 5 label simply provides an identifier to a 4 statement, and lets you refer to it elsewhere 3 in your program.

IMHO, this pseudo-protocol 2 is only useful for bookmarklets...

Recommended 1 article:

Score: 6

As other answers have mentioned, avoid the 16 use of javascript: href links, and it is entirely unnecessary 15 in event handler attributes. However, since 14 A tags are sometimes still semantically correct, you 13 will need to put something in the href attribute 12 if you want your :link and :hover CSS styles to be 11 applied to the element in Internet Explorer. In 10 this case, use:

<a href="#" onclick="doSomething(); return false;">Link</a>


<a href="javascript://" onclick="doSomething();">Link</a>

There is one (somewhat 9 obscure) bug with the javascript protocol - in Internet 8 Explorer*, it will think you are leaving 7 the page when you click the link. If you 6 are using window.onbeforeunload, then your navigate-away message 5 will appear at this time. For this reason 4 alone, we've stopped using the javascript protocol 3 completely so we don't have this bug show 2 up because we forgot to check for it when 1 we add a navigate-away message to some page.

* I probably should have specified the version when I first wrote this. I don't remember at all, but just in case the bug is present only in a now-mostly-defunct browser like IE 6 or 7, you are probably best to test it yourself.

Score: 5

Don't specify it at all, ever. It's wrong 6 to do it in <a> tags, which instead should 5 be coded like this:

<a href='#' onclick='alert("Hello")'>World</a>

It's a remnant from days 4 gone by. The only time I can think of where 3 it's used would be in the browser address 2 bar (and bookmarklet bookmarks). Keep it 1 out of your pages.

Score: 2

In practice, you are correct.

You need to 9 do this in any instance where something 8 other than script is expected. In theory, you 7 can stick javascript:whatever anywhere you can use a URL, but 6 this was never supported and now is officially 5 recommended against use.

However, you really shouldn't 4 use javascript: at all. For links, you can use the 3 onclick attribute. What is actually happening nowadays 2 is the JavaScript engine is identifying 1 javascript: as a label, which is why the code executes.

Score: 1

You should all check out http://bytes.com/topic/javascript/answers/504856-javascript-pseudo-protocol-event-handlers Especially the 13 post by "Lasse Reichstein Nielsen",because 12 most answers are here are incorrect in some 11 fashion.

Also remember that the anchor tag 10 does not require a href at all! That is <a>hi</a> is 9 valid xhtml. The problem using href="#" is that 8 it may scroll to the top of the page.. it 7 is simply not needed. Lastly if you do not 6 actually want the behavior of the anchor 5 tag you should not use it. You can simulate 4 an anchor using css (cursor:pointer) and events like mouseenter 3 and mouseleave (which is more work, but 2 does not "break" the expected 1 behavior of an anchor tag).

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