abp/docs/en/UI/AspNetCore/JavaScript-API/Modal-Manager.md

ASP.NET Core MVC / Razor Pages UI: JavaScript Modal Manager

abp.ModalManager is used to easily manage a modal dialog in your application.

Example: A modal dialog to create a new role entity

While you can always use the standard Bootstrap API (or another library) to create modal dialogs, abp.ModalManager provides the following benefits;

• Lazy loads the modal HTML into the page and removes it from the DOM once its closed. This makes easy to consume a reusable modal dialog. Also, every time you open the modal, it will be a fresh new modal, so you don't have to deal with resetting the modal content.
• Auto-focuses the first input of the form once the modal has been opened.
• Automatically determines the form inside a modal and posts the form via AJAX instead of normal page post.
• Automatically checks if the form inside the modal has changed, but not saved. It warns the user in this case.
• Automatically disables the modal buttons (save & cancel) until the AJAX operation completes.
• Makes it easy to register a JavaScript object that is initialized once the modal has loaded.

So, the ModalManager makes you write less code when you deal with the modals, especially the modals with a form inside.