javascript void functions [duplicate]

Question

Possible Duplicate:
What does “javascript:void(0)” mean?

I want to ask a few questions regarding javascript:void(0)

<input type='submit' name='btn' value='submit' onClick='javascript:void(0)' />

Can you please explain void(0) - is it a built-in function? Does the keyword javascript represent that the code is written in javascript? If there is anything weird that you know about it, please share it with me. Thank you.

Answer 1

void():

This operator allows inserting expressions that produce side effects into places where an expression that evaluates to undefined is desired.

The void operator is often used merely to obtain the undefined primitive value, usually using "void(0)" (which is equivalent to "void 0"). In these cases, the global variable undefined can be used instead (assuming it has not been assigned to a non-default value). Note, however, that the javascript: pseudo protocol is discouraged over other alternatives, such as unobtrusive event handlers.

You can read more on this similar thread: What does "javascript:void(0)" mean?

Answer 2

javascript:void(0) can be considered as "Do nothing". Not sure what was intended to be achieved with it here. If you wanted to prevent form submission on button click, you should have used something like

<input type='submit' value='submit' onClick='return false;' />

Answer 3

void is an operator that is used to return a undefined value so the browser will not be able to load a new page. An important thing to note about the void operator is that it requires a value and cannot be used by itself.