How to determine if an Office Add-in is running under Excel or Excel Online?

Question

I\'m writing an Office Add-in (formerly, Apps for Office). I\'m using office.js and in some point of code I want to check if the app is running in excel (deskto

Answer 1

Inspired by Sturb's answer, the following works with ExcelApi 1.10 & 1.12

if (window.top.window == window) {
  // Add-in is running in Excel desktop
} else {
  // Add-in is running in Excel online
}