NULL ^= NUL
It grieves me that someone who pretends IT competence doesn't ken the difference between NUL and NULL.
NUL is the name of the (ASCII) character with the binary value of 0000 0000.
NULL is empty, not value, undefined. As in a NULL pointer, a pointer that has not been initialised.
A NUL is commonly used in programs (and hence the strings of characters the use) to denote the end of a string, and this would be why Internet Exploder ignores them.