HUD controll

hey guys! i have a quick question that i hope is easy to ansnwer. i was wondering how to control a show hide script from a HUD as well as using normle key commands.

show()
{
llSetAlpha(1.0, ALL_SIDES);
}

hide()
{
llSetAlpha(0, ALL_SIDES);
}

default
{
state_entry()
{

llListen(10,"",NULL_KEY,"";
}

listen(integer channel, string name, key id, string message)
{
if(llStringLength(message)!=4)
return;

message = llToLower(message);

if(message == "show"
{
show();
return;
}
if(message == "hide"
hide();
}
}