how to chang visibility in asp with vbscript

How to button visible true or false in ASP with vbscript

<textarea <% if Session("a") = "a" %> class=开发者_C百科"a" <% else %> class="b" <% end if %>

<input type="button" id="clonebutton" value="clone" />

if session is a, button is visible else button is invisible. How can I do for that?

Your code is not fully formed, and I'm not sure what that textarea is doing there, but simply put this around your button:

<%If Session("a") = "a" Then%>
   <input type="button" id="clonebutton" value="clone />
<%End If%>

You probably shouldn't have session variables floating around with un-descriptive names such as "a", but maybe you were just making an example.