You can create Web pages with optional sections that are shown only if certain criteria are met. For instance, if you are creating an online FAQ (frequently asked questions), you may initially hide the answers and show them if the user wishes to see them.
ASP.NET controls have a visible property that controls whether the controls are rendered. If the value of this property is set False, the control is not displayed on screen.
Web controls also have an Enabled property. If this property is set False, it appears on screen but does not function. IE 4.0 and higher versions display the control as grayed out. Other browsers may show the control normally but it does not function.