When do I need to specify the JavaScript protocol?

javascript correctness
cgp picture cgp · Feb 23, 2010 · Viewed 8.2k times · Source

I was under the impression that I only need to specify the "protocol" when using JavaScript in URL attributes, such as in hrefs. Is this the only "useful" context for javascript:?

Sensible:

<a href="javascript:alert('Hello')">World!</a>

Silly:

<form onsubmit="javascript:alert('oops!')">

Is this right? Or is there some obscure bug/use case I need to be aware of?

Answer

Christian C. Salvad&#243; picture Christian C. Salvadó · Feb 23, 2010

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

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

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

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