function BHOP()
local me = LocalPlayer()
  if  input.IsKeyDown(KEY_SPACE) and me:IsOnGround() then
     me:ConCommand("+jump")
  end
  if input.IsKeyDown(KEY_SPACE) and not me:IsOnGround() then
    me:ConCommand("-jump")
  end
end

hook.Add("Think","bhopgay",BHOP)