Add a new User Custom Action to a site collection in SharePoint

Use the code below to create a new User Custom Action which will automatically run on ALL pages within a site collection, this is very useful for creating global design themes or code files that you want to run across all sites within a site collection (including the site collection top level site)

[csharp] $username = "someone@domain.com" $password = Read-Host -Prompt "Please enter your password" -AsSecureString $url = "https://tenant.sharepoint.com/sites/sitename" Add-Type -Path "c:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.dll" Add-Type -Path "c:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.Runtime.dll" # connect/authenticate to SharePoint Online and get ClientContext object.. $clientContext = New-Object Microsoft.SharePoint.Client.ClientContext($url) $credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, $password) $clientContext.Credentials = $credentials if (!$clientContext.ServerObjectIsNull.Value) { Write-Host "Connected to SharePoint Online site: ‘$Url’" -ForegroundColor Green } $site = $clientContext.Site $sca = $site.UserCustomActions; $clientContext.Load($sca) $clientContext.ExecuteQuery() $newCustomAction = $sca.Add() $newCustomAction.Name = "DisplayNameOfAction" #give it a name – a date format usually works well $newCustomAction.Sequence = "1000" #set the sequence of when the file should be loaded – the higher the number it is then it will be loaded after the other files $newCustomAction.Title = "Global Brading JS and CSS" $newCustomAction.Description = "Global Branding JS and CSS script link added by Username on 02/08/2017" $newCustomAction.RegistrationType = "None" $newCustomAction.Location = "ScriptLink" #leave this as is $newCustomAction.ScriptSrc = "https://tenant.sharepoint.com/_catalogs/masterpage/JS/somefile.js" #URL to the file in question $newCustomAction.Update() #apply the changes $clientContext.Load($newCustomAction) $clientContext.ExecuteQuery() [/csharp]