It's because you're calling param() in a list context, so for the non-existent parameter you get an empty list. It's just as if you had done

my %hash = (
   'foo' => (),
   'bar' => 'baz'
);                           # which is the same as ...

my %hash = (
   'foo', 'bar', 'baz'
);

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PerlJam

In reply to Re: Strange behaviour - cgi related by duff
in thread Strange behaviour - cgi related by kiat

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