How to: Convert HTML Server Controls to HTML Elements
If you no longer need to program an HTML server control in server code, you should convert it back to a plain HTML element. Each HTML server control in a page uses resources, so it is a good practice to minimize the number of controls that the ASP.NET Web page has to work with.
To convert an HTML server control to a HTML element
Remove the attribute runat="server" from the control's tag.
You do not have to remove the ID attribute. You want to be especially careful not to remove the ID attribute if there is client script that references the element.