</texcode>
You can switch the visibility of layers with the JavaScript functions HideLayer and VideLayer(from {{src|scrn-fld.mkvi}}: <texcode>\defineviewerlayer[test] \startviewerlayer[test]Hide Me\stopviewerlayer \defineoverlay [WithTest] [{\overlayrollbutton[HideLayer{test}][VideLayer{test}]}] \framed[background=WithTest]{toggle}</texcode>
Viewer layers are known to work within {{cmd|setlayer}} (see [[Layers]]), e.g. {{src|meta-ini.mkiv}}.