shop script help once again

[GULTHEX]

PHP Code:

function onCreated()
{
  setshape 1,32,32;
}
function onActionbuy()
{
  if(playerrupees>=100)
  {
    addweapon Event/Headbob;
    playerrupees-=100;
  }
}
//#CLIENTSIDE
function onPlayerchats()
{
  if(player.chat=="buy Headbob")
  {
    triggeraction(x,y,"buy","buy");
    //the level npc triggeraction type
  }
} 


when i put this in a lvl npc and say buy Headbob nothing happens

how do i fix it???