Syed,
> What is the actual meaning of "!" operator? At which places it is needed
> to be used? Where can I use it? And where I cannot use it?
It means "not". It is typically used with != to mean "not equal", and
with Boolean values to mean "not true" or "not false" (usually to mean "not
true") [1]. For instance:
var blnVal = false ;
if (blnVal == false)
{
// do something here...
}
is the same as
var blnVal = false ;
if (!blnVal)
{
// do something here...
}
James Aylard
1.
http://developer.netscape.com/docs/manuals/js/client/jsref/ops.htm#1062688