Instead of adding your JavaScript snippet in the source of the SharePoint Content Editor web part, you can add a link to a JavaScript file: http://www.kalmstrom.com/Tips/SharePoint-Online-Course/Content-Editor-JavaScript-Link.htm
Manage SharePoint Permission levels on sites, apps, pages and items. Learn how the inheritance work and how to stop it: https://kalmstrom.com/Tips/SharePoint-Online-Course/SharePoint-Permissions.htm
Facilitate SharePoint permission management in by creating Security Groups: http://kalmstrom.com/Tips/SharePoint-Online-Course/SharePoint-Permissions.htm
