Just worked on the same problem today – guess I was lucky
The command line therefore is
set myarg=blabla && start "" "c:\Program Files\EmEditor\EmEditor.exe" /mf "d:\tmp\mymacro.jsee
The macro file code then is
var she = new ActiveXObject("wscript.shell");
myarg = she.ExpandEnvironmentStrings("%myarg%");
alert(myarg);There is one important issue though:
Emeditor must not yet run when calling. Most likely because once running it would only have access to environment variables which existed upon starting EmEditor
Hope this helps
Patrick
PS Credits for those who brought me on the right path:
https://www.emeditor.com/forums/topic/macro-scripting-importexport-of-filter-settings/
https://stackoverflow.com/questions/21315708/reading-environment-variables-with-javascript
https://superuser.com/questions/424001/launch-windows-program-with-custom-environment-variable