pdefine the function in the HEAD so that it’ll be
available when it’s called.
p
pfunction is not executed till it is called.
p
ponce the function is defined in the HEAD, it can be
called just like a predefined
function.
p
pto include a user-defined function in a page, the
simplest way is to include its
definition in SCRIPT tags in the HEAD so it will be ready for use.