getUserLoginID is deprecated. Instead use
Deprecated. As of June 24, 2013, replaced by getEmail()
Gets the user's email address, if available. If security policies do
not allow access to the user's email address, this method returns a
blank string. The circumstances in which the email address is
available vary: for example, the user's email address is not available
in any context that allows a script to run without that user's
authorization, like a simple onOpen(e) or onEdit(e) trigger, a custom
function in Google Sheets, or a web app deployed to "execute as me"
(that is, authorized by the developer instead of the user). However,
these restrictions generally do not apply if the developer and the
user belong to the same Google Apps for Business domain.
// Log the email address of the person running the script.