Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Select 1 face-up monster your opponent controls during each of your Standby Phases. It loses 500 ATK until the end of this turn.
--アマゾネスの吹き矢兵
--Amazoness Blowpiper
local s,id=GetID()
function s.initial_effect(c)
	--atkdown
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_ATKCHANGE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_F)
	e1:SetCode(EVENT_PHASE|PHASE_STANDBY)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return Duel.IsTurnPlayer(tp)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsControler(1-tp) and chkc:IsLocation(LOCATION_MZONE) and chkc:IsFaceup() end
	if chk==0 then return true end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	Duel.SelectTarget(tp,Card.IsFaceup,tp,0,LOCATION_MZONE,1,1,nil)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) and tc:IsFaceup() then
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetValue(-500)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		tc:RegisterEffect(e1)
	end
end