Macros for pet attacking?

[Jadvya]

Is there a style of macro I can use to get my pet to attack enemies without having to click the button on his bar when he's in defensive mode? I tried using a macro I got from Googling around:

/cast Hunter's Mark
/script PetAttack()

But each time I do it, I get an error that "A macro script has been blocked from an action only available to the Blizzard UI." Anything I can do about this?

[GormanGhaste]

wouldn't it be

/cast Hunter's Mark
/cast PetAttack

?

Edit: oh good, someone who knows what they're doing arrived

[Rykochet]

#showtooltip
/cast Hunter's Mark
/petattack

[Jadvya]

#showtooltip
/cast Hunter's Mark
/petattack

This is the one! Thank you so much!