Sharepoint 2013 workflow initiation form with people picker

Using a WorkflowInitiationForm in an VisualStudio workflow for SharePoint 2013 I wonder how to get the Information from people picker. Adding to the project the form delivers code examples for string, integer and datetime, but not for the used people picker.

Is it something like

params['users'] = document.getElementById("ctl00_PlaceHolderMain_???PeoplePicker???").value;

to pass the value(s) to the startWorkflow() parameters? And how to get multiple users?

useful links:

• blog.loitzl.com