I know this can be done, what am I doing wrong?

If you have form objects on a page with the same name
they are automatically put into an array

This is what Im trying to accomplish since I do not know
how many of these objects will be created when the page
loads. So i need to use the ubound to control the loop.
It comes back as AttributePermissions undefined when it
hits the ubound statement. if I say (x<=a static value)
it works fine

x=0;
do
{
document.MySecurity.AttributePermission
[x].disabled='disabled';
document.MySecurity.AttributePermissions[x].checked=true;
x=x+1;       
}while(x<=ubound(AttributePermissions));

also tried                while
(x<=document.MySecurity.AttributePermissions.ubound);  
with same error message