Copy Selected Items from one SharePoint List to another

There are a lot of code examples out there, but I have not found a complete JavaScript code that combines all of them.

Requirement

The reuirement is that you can select multiple SharePoint list items in one list and when you click a button these items get copied to another list (in my case “list2”).

The Code

This is a code example that you will have to adjust to your requirements and environment.
I copied most of the lines from other blogs and forums and assembled them to meet my expectations.

So the honor goes to all the developers out there that helped me with their code snippets.

Copy the code to a txt file and save the file on the SharePoint Site within the SiteAssets library.

Add a CEWP (Content Editor Web Part) to the list view and use the link to that text file as the source.