onclick="javascript:func()" vs. onclick="func()" [duplicate]

Question

Is there any difference between

<input type="submit" value="Register" onclick="javascript:submitTheForm();">

and

<input type="submit" value="Register" onclick="submitTheForm();">

Should I use javascript: before a JS function call?

Answer 1

javascript: inside an onwhatever="" handler is a no-op. The content of this attribute is always JavaScript so javascript: defines a label - but outside of a switch block or a loop (where you can use it to break/continue to the position of the label) it does nothing.

However, using inline event handlers is discouraged, there are better ways to register event handlers.

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While not mentioned in the question, it's worth noting that using javascript: in the href attribute does work (and in there it is actually necessary) but is highly discouraged for various reasons:

• this does not point to the element
• Calling a function returning a value causes the browser to leave the site
• Clicking the link with disabled JavaScript breaks
• Trying to open the link in a new window/tab breaks

So, if you really have to use inline events, always use onclick="" etc. without javascript:.

Answer 2

When you are in a onclick attribute, you shouldn't use the javascript: prefix. This is usefull when you want a link <a /> to handle a JS function, for example:

<a href="javascript:myfunc();"></a>