How to activate and run JavaScript in AppleScript? I'm trying to run simple script in AppleScript Editor on OS X 10.9.5, but using JavaScript, e.g.:

var SE = new Application("System Events");
SE.processes.windows.name()


However my dropdown only shows AppleScript.

How do I activate JavaScript if it isn't appearing on the list? It is also not in Preferences/General.
You cannot. JavaScript for Automation was only introduced in OS X 10.10 Yosemite.

AppleScript Editor.app was also renamed to Script Editor.app due to it now not only being for AppleScript.