Invoking functions across frames

I'm trying to invoke user defined function
by js HREF that resides in another frame that uses a function in the frame that invoked it.
Here's the barebones of the issues:

header frame :
function doit() {
document.write("here i am")
}
<a href="javascript:go()" target="main"> X </a>
--------------------------------------
main frame :
function go() {
parent.frames[0].focus()
doit() };

-------------------------

When I click on X in header form it gives
me error saying "object expected" referring
to the doit() function as if it didn't exist.

<a href="javascriptarent.mainframename.go();">X</a>

Spookster