sending variable from one jsp to another jsp

You have a number of options:

1. Store it in the session.

   // Memorise any passed in user.
   String username = request.getParameter("username");
   if (username != null && username.length() > 0) {
     session.setAttribute("username", username);
   }
   

2. Store it as a hidden field in the form.

   <input name="username" type="hidden" value=""/>
   

3. Store it in a cookie.

   username = getCookie(userCookieName);
   
   // Get from cookie.
   function getCookie(name) {
     if (document.cookie) {
       index = document.cookie.indexOf(name);
       if (index !== -1) {
         f = (document.cookie.indexOf("=", index) + 1);
         t = document.cookie.indexOf(";", index);
         if (t === -1) {
           t = document.cookie.length;
         }
         return(document.cookie.substring(f, t));
       }
     }
     return ("");
   }
   

4. Persist it on the client side in sessionStorage. See here for details.

   sessionStorage.setItem("username", "...");
   

5. Not really another option but a mechanism – pass it in the URL:

   .... onclick="window.location='details.jsp?username=...'