User controls let you create reusable components that can be added to multiple pages on a web site. Controls have HTML like normal web pages, but don't require the head and body element structure of normal web pages. A user control can be placed anywhere on a web page by adding a Register directive at the top of the HTML file and placing the element on the page where you want it to appear. With a single control on multiple web pages, any change to that one control will appear on every web page to which the control is added. Employing user controls on your web sites enables you to become more productive by decreasing initial development time and saving huge amounts of time during site updates.