SP.UserCreationInformation.loginName property (sp.js)
Gets or sets a value that specifies the login name for the user to be created.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.UserCreationInformation.get_loginName ()
var value = SP.UserCreationInformation.set_loginName ()
Return value
Type: String
Remarks
It must not be null. It must not be empty. Its length must be equal to or less than 251.