Описание тега asp.net-core-tag-helpers

ASP.NET Core MVC TagHelpers are server-sided classes used for rendering HTML content. They react to specific HTML tags or attributes within Razor views, and can alter and generate new markup. They're a modern alternative to the ASP.NET MVC Html Helpers.

ASP.NET Core MVC TagHelpers enable server-sided code for rendering additional HTML content in Razor View templates, like validation or rendering commonly used components.

Unlike Html Helper calls, the TagHelpers are HTML-friendly and better blends in the Razor HTML templates.

Official ASP.NET Core TagHelper Documentation