forcing variable declaration

I've looked at the manual and php.ini file, but can't find what I'm looking for. Is there a way to make PHP force that variables be declared? (In VBScript, variables do not have to be declared unless "OPTION EXPLICIT" appears at the top of the script. I'm wondering if PHP has an equivalent). I hate it when a typo creates a variable at run time and the script continues (and produces unwanted results). Thanks. TIM -My definition of a free society is a society where it is safe to be unpopular. -Adlai E. Stevenson