Get user email address client side

Question

I am using the following code (below) in a IE 11 browser on SharePoint 2013 on premises to successfully to return the user and email address - however I am unable to get the email to pass to a variable to use for a later third party script.

Please can someone advise how pass the email out to a variable - All the usual methods leave the variable undefined?

var clientContext;
var user;

// Make sure the SharePoint script file 'sp.js' is loaded before your
// code runs.
SP.SOD.executeFunc('sp.js', 'SP.ClientContext', sharePointReady);

function sharePointReady() {
    clientContext = SP.ClientContext.get_current();
    user = clientContext.get_web().get_currentUser();

    clientContext.load(user);
    clientContext.executeQueryAsync(onQuerySucceeded, onQueryFailed);
}
function onQuerySucceeded() {
    alert('The email address of the current user is ' + user.get_email());
    alert('The account name is ' + user.get_loginName());
}
function onQueryFailed(sender, args) {
    alert('Error: ' + args.get_message());
}

Answer 1

Is it just email that is null? If so, it might be unset/unavailable.

Is it possible, that you access user variable before it initialized?

sharePointReady, and onQuerySucceeded are async. Probably you should add you code in the end of onQuerySucceeded.