SharePoint 2013 has introduced a small Focus on Content icon to the ribbon bar which, for the MasterPages that support it, will show and hide portions of the page when clicked. This can be useful for hiding non-essential page elements.
When the icon is clicked, JavaScript will do two things:
- It creates a cookie, so the selection is remembered the next time the page is visited.
- It adds a new ms-fullscreenmode class to the page’s BODY tag.
So, via CSS, we can decide which elements of the page should be hidden via the Focus on Content functionality.
.ms-fullscreenmode #nonessentialcontent { display: none; }