How to technically implement project widget loading via JS?

Question

JavaScript

I am making an electronic recording project that provides integration with other projects through a calendar widget. The calendar is completely custom (not fullcalendar and not jquery event calendar). You need to make sure that it is loaded using a js script on the page of a third-party project, embedded in the layout - i.e. it should not "float" somewhere in the corner of the page, as in the common case with technical support chats, namely embedded.
Is it possible to do this, will there be problems with the Same Origin Policy?
By the way, how are chats in the lower right corner of the page technically implemented - for example, do VK, Bitrix 24, all kinds of online consultants have this?

Answer 1

positioning. try to embed such a thing on a test site, we'll see