Also note, the red rectangle that appears on the top right corner means the system uses sync scrolling, instead of APZC. Refer to [https://bugzilla.mozilla.org/show_bug.cgi?id=1053992 bug 1053992] for more info.
== Find the Pixel Ratio ==
In WebIDE, Runtime choose your device(it needs to turn on the debugging via USB from device in Developer's page of Settings app) then Open the system app. In the concole tab, enter "window.devicePixelRatio" in command line to get the pixel ratio of screen.
<gallery>
File:PixelRatio.jpeg
</gallery>
= Scripts =