HTML Horizontal Rule Control
One control based on the HTML hr element is available on the HTML tab of the Toolbox as the Horizontal Rule control.
HTML server controls added from the Toolbox to a page in Visual Studio are simply HTML elements with certain attributes already set. You can also create HTML elements in Source view by typing markup.
By default, HTML elements on a Web Forms page are not available to the server; they are treated as markup that is passed through to the browser. However, if you add an id attribute and the attribute runat="server", ASP.NET recognizes the element as a control on the page and you can program it with server-based code. If you convert an HTML hr element to an ASP.NET server control, it is created as an instance of the HtmlGenericControl class. For more information, see ASP.NET Web Server Controls Overview. For a list of these controls, see HTML Server Controls.