It isn't really clear from what you posted exactly what you are trying to accomplish. Do you want a Roku screen that updates every few minutes? Do you want an image that updates every few minutes? As you probably know, a Roku can't really display a web (html) page. Instead, the Roku can take XML data and render that in many different ways. To do something on a timer, one can easily create a timer and perform an action on a regular schedule:
timer=createobject("rotimespan")
timer.mark()
while true
if timer.totalseconds() > 60 then
doMyThing()
timer.mark()
end if
end while
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