Modify Regional and Language settings with JSOM and JavaScript

Recently, the ability to modify the Regional and Language settings of a site has been added to the client APIs in SharePoint 2013 and SharePoint Online. While the support for SharePoint 2013 was added in the December 2014 CU (as announced by Vesa here), the support for SharePoint Online has been a more recent addition.

There are some really nice code examples for the CSOM Regional and Language APIs in the Office Dev PnP Library:
https://github.com/OfficeDev/PnP/tree/master/Samples/Core.Settings.LocaleAndLanguage

But, I could not find JSOM code example of these APIs. So I am listing down some of the most frequently used Regional and Language functions here.

1) Add a Supported UI Language:

2) Remove a Supported UI Language:

3) Disable Multi Lingual and Remove all UI Languages:

4) Get Regional Settings:

A full list of all the regional settings properties is available here:
https://msdn.microsoft.com/EN-US/library/office/jj244880.aspx

5) Set Regional Settings:

6) Set Time Zone of a site:

This one was a bit tricky but I finally got there in the end. You will need to know the ID of the Time Zone you want to set in the site. A full list of SharePoint TimeZone IDs is here:
https://msdn.microsoft.com/library/microsoft.sharepoint.spregionalsettings.timezones.aspx



Hope this helps!