SpellDuration
When we need to know the duration of a spell effect, we call scripts by the name "SpellDuration". If the scripts return any non-empty value then that value is used as the spell's duration.. The value can be any integer or fractional value such as "12" or "3.25".
Parameters
Parameter [5] = the duration as computed from the spell editor definition. This is the value that will be used if no script exists or if the script returns an empty result.
Context
Attacker - the character that cast the spell
spell - the spell that is being cast