javascript identity.login not working

[#1]

I have created an Adobe Acrobat form that has a textbox that retrieves the windows logged in user using JavaScript with identity.login. This works fine when the document is opened with the Adobe Reader. I have uploaded the document to our SharePoint Online. The document now opens in the browser in SharePoint Online, but, fails on retrieving the login of the user. How can I make this work?

[#2]

I have created an Adobe Acrobat form that has a textbox that retrieves the windows logged in user using JavaScript with identity.login. This works fine when the document is opened with the Adobe Reader. I have uploaded the document to our SharePoint Online. The document now opens in the browser in SharePoint Online, but, fails on retrieving the login of the user. How can I make this work?

[#3]

Perhaps you are no longer using Adobe technology. What browser is it? You say it "fails" - what is the failure?

[#4]

The browser is IE 11. The text box returns Undefined instead of the login, (e.g., abc1). The Adobe PDF Reader plugin is Enabled.

Name:                   Adobe PDF Reader

Publisher:              Adobe Systems, Incorporated

Type:                   ActiveX Control

Architecture:           32-bit and 64-bit

Version:                17.12.20093.238000

File date:              ‎Monday, ‎July ‎31, ‎2017, ‏‎6:31 PM

Date last accessed:     ‎Today, ‎December ‎13, ‎2017, ‏‎5 hours ago

Class ID:               {CA8A9780-280D-11CF-A24D-444553540000}

Use count:              0

Block count:            94

File:                   AcroPDF64.dll

Folder:                 C:\Program Files (x86)\Common Files\Adobe\Acrobat\ActiveX

[#5 · Accepted solution]

Did you read the reference entry for the "Identity" object?

Acrobat DC SDK Documentation

This object is protected and requires a privileged context.  There is no way it could have worked in Reader unless, it was in a stamp script.