Make user restrict to open AR Experience in Laptop/Mac

Hi,
i have created one AR Exp in which i used image tracking and i have used <XRWEB="disableWorldTracking:true ">
but while using that i am not able to get the msg/Screen when user open this on laptop.
i have to restrict the user to open this AR Exp in laptop so i have created custom screen for that but using this i am not able to get that.

Are you trying to restrict your experience to desktops only?