Counting Event Observers with Prototype 1.6

// Counting Event observers with Prototype 1.6

javascript:alert(
    "Event Observers\n" + $H(Event.cache).inject( $H(),
        function (acc, p) {
            $H(p.value).each(
                function (evtT) {
                    if ( !acc.get(evtT.key) )
                        acc.set(evtT.key, 0);
                    acc.set(evtT.key,
                        acc.get(evtT.key) + evtT.value.size()
                    );
                }
            );
            return acc;
        }
    ).inject( "",
        function (acc,p) {
            acc += "\n"
                + p.key
                + ":"
                + "\t"
                + p.value;
            return acc;
        }
    )
)