What are HTML server controls and Web controls ?

HTML Server controls: HTML elements are completely client-based; the server has no knowledge of any of these controls. A browser knows what <input type="text"> is supposed to look like and renders it accordingly. HTML server controls are server-side elements. They're objects that are created on the server, with properties, methods, and events that you can handle. They generate HTML for the browser to display. HTML server controls are very easy to create—simply add the runat="server" attribute to any HTML element. Every HTML element has a corresponding HTML server control. <input type="text" id="MyTextBox" runat="server" />Once you turn an HTML element into an HTML server control, every attribute of the element can be modified through code. Web controls: Web server controls are similar to HTML server controls. They're created on the server and allow you to build complex user interfaces easily. They require the runat="server" attributes to work correctly. They also provide rich programmatic capabilities. Unlike HTML server controls, however, Web controls don't necessarily map one-to-one to HTML elements and can represent more complex UI elements.