Using templates and slots - Web APIs | MDN - MDN Web Docs

mdn slot Slots are identified by their name attribute, and allow you to define placeholders in your template that can be filled with any markup fragment you want when the element is used. An element with a slot attribute is assned to the slot created by the slot> element whose name attribute's value matches that slot attribute's value.

mdnsport live chat, We'll discuss using the template> and slot> elements, the slot attribute, and JavaScript to create a template with an encapsulated Shadow DOM. We'll then re-use.