HOW TO CONVERT HTML CONTROLS TO ASP CONTROLS ?.

Question

 

I want to know ,how to convert to Html controls to asp controls..can You any body give me a simple example...? 

i know if i mentioned Runat="server"..it is treated as asp controls..i want to know if  any other method is there ?.

and what is the need to convertion ?. 

 

 

Thank you,

 Pavan .