Easy Function Question?

I have a need to call a function, where all the variables used might not be set. Is there a way to have a variable in a function have a default setting if the variable passed to the function is VOID? EXAMPLE: $name="me"; $phone="5555"; //$zip is VOID function myFunction($name, $phone, $zip){ echo $name.$phone.$zip } can I write...? function myFunction($name, $phone, $zip="6666"){ echo $name.$phone.$zip } and then $zip will have a value of 6666 if $zip is VOID for some reason...? I thought it was something like this, but I keep batting ZERO and there is no mention of this problem in the places I looked in the docs. Can anyone throw me a bone? Thanks gang! -NorthBayShane