How to use while/do function in IE automation ?

[naru]

i want to repeat this function 

_IELoadWait($oIE, "url 2")
$checkb = _IEGetObjById($oIE,"checkb")
_IEAction($checkb,"click")

$img = _IEGetObjById($oIE,"img")
_IEAction($img,"click")

_IELoadWait($oIE, "url 1")
$btnfy = _IEGetObjById($oIE,"btnvfy")
_IEAction($btnfy,"click")

until my targeted webpage not found.

[Earthshine]

I would open the help file online or local, and search for While