If you have a long list of items on a web page and you want to visually separate them into different sections, you could use the SeparatorElement to add a horizontal line between the sections. Other examples include creating custom buttons, menus, and forms.
Overall, the Web Components API provides a powerful way to create reusable and modular components for web pages, and this code snippet demonstrates how to create a simple custom element using this API.
Content above the separator
Content below the separator
The "connectedCallback" method is called when the custom element is inserted into the DOM (i.e., the web page). This method sets the display style of the element to "block" (which means it takes up the full width available) and adds a 1-pixel solid black border to the top of the element.
The "customElements.define" method registers the custom element with the browser so that it can be used in HTML documents. The first argument to this method is the name of the custom element (in this case, "separator-element"), and the second argument is the class that defines the element.