Problem in code provided by this c-sharpcorner

Question

Hi !! There is a code that written by Frederick Volking on the provided link. it gives me an error Can yoo please help??? < a href="http://www.c-sharpcorner.com/Code/2003/Sept/ModalPopupInASP.NET.asp"> link http://www.c-sharpcorner.com/Code/2003/Sept/ModalPopupInASP.NET.asp Thanks in advance. it compiles fine but gives page error when click on the button