这个AJAX / JSP代码有什么问题？

Question

当我前两次点击搜索按钮时，它没有显示任何内容。然后再次点击它会显示第一次搜索的结果，所以基本上结果会延迟2次'搜索'点击。

表格只是闪烁，不会保持可见。为什么呢？

/*this is the code for the servlet*/

case "/ViewArchive":
    String line = "";
    searchString = request.getParameter("searchString");
    searchBy = request.getParameter("searchBy");
    searchType = request.getParameter("searchType");
    if(searchString.isEmpty()==false)
    {
        if(searchType.equalsIgnoreCase("major incident"))
        {
            mi = new DBManager().getArchiveMajorIncident(searchString, searchBy);                                      
            request.getSession().setAttribute("majorincident", mi);
        }
        else if(searchType.equalsIgnoreCase("elevated ticket"))
        {
            et = new DBManager().getArchiveElevatedTicket(searchString, searchBy);                                  
            request.getSession().setAttribute("elevatedticket", et);
                            }
        }
        else if(searchType.equalsIgnoreCase("open critical/high issue"))
        {
            oh = new DBManager().getArchiveOpenCriticalHighIssue(searchString, searchBy);                                   
            request.getSession().setAttribute("opencriticalhighissue", oh);
        }
    }

/*
request.getSession().removeAttribute("searchType");
request.getSession().setAttribute("searchType",searchType);
request.getRequestDispatcher("viewhistory.jsp").forward(request, response);
*/

**JSP PAGE**

<div class="center">
    <div class="search">
    <form>
        Search: 
        <input id="searchString" type="text"  name="searchString" >&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
        Type: 
        <select name="searchType" id="searchType">
            <option>Major Incident</option>
            <option>Elevated Ticket</option>
            <option>Open Critical/High Issues</option>            
        </select> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

       By: 
       <select name="searchBy" id="searchBy">
           <option>EM No.</option>
           <option>IM No.</option>
       </select>

       <button class="myButton searchBtn" id="searchBtn" type="submit" value="submit">Search</button>
    </form>
    </div>

   <h3 style="display:none"></h3>
   <table style ="display:none" id = "MajorIncidentsTable" width="100%">
       <colgroup> 
           <col style="width:8%">
           <col style="width:11%">
           <col style="width:20%">
           <col style="width:8%">
           <col style="width:20%">
           <col style="width:10%">
           <col style="width:10%">
           <col style="width:11%">
       </colgroup>  
       <tr>  
           <th>EM#</th>
           <th>Date Opened</th>
           <th>Description</th>
           <th>Current Status</th>
           <th>Next Action Step/s</th>
           <th>Technical Owner</th>
           <th>Ownership</th>
           <th>Checkpoint Schedule</th>
       </tr>
       <tbody>
       <c:forEach var="c" items="${majorincident}" varStatus="counter">
            <tr>
                <td>${c.em_no}</td>
                <td>${c.dateopened}</td>
                <td>${c.description}</td>
                <td>${c.current_status}</td>
                <td>${c.next_action_steps}</td>
                <td>${c.technical_ownership}</td>
                <td>${c.owners}</td>
                <td>${c.checkpoint_schedule}</td>
            </tr>
        </c:forEach>
        </tbody>
    </table>
</div>

/* This is in the JSP page too */

<script type="text/javascript">
    $(document).ready(function(){
        /* if(
               $majorincident != null 
               || $elevatedticket != null 
               || $opencriticalhighissue != null){

        } */

        $("#searchBtn").click(function(){
            var name = $("#searchString").val();
            var type = $("#searchType>option:selected").text();
            var by = $("#searchBy>option:selected").text();

            if(type=="Major Incident"){
                $("h3").css('display', 'block');
                $("#MajorIncidentsTable").css('display', 'block');
                $("#ElevatedTicketsTable").css('display', 'none');
                $("#OpenCriticalHighIssuesTable").css('display', 'none');
                $('h3').replaceWith(type);
            }
            else if(type=="Elevated Ticket"){
                $("h3").css('display', 'block');
                $("#MajorIncidentsTable").css('display', 'none');
                $("#ElevatedTicketsTable").css('display', 'block');
                $("#OpenCriticalHighIssuesTable").css('display', 'none');
                $('h3').replaceWith(type);
            }
            else if(type=="Open Critical/High Issues"){
                $("h3").css('display', 'block');
                $("#MajorIncidentsTable").css('display', 'none');
                $("#ElevatedTicketsTable").css('display', 'none');
                $("#OpenCriticalHighIssuesTable").css('display', 'block');
                $('h3').replaceWith(type);
            }

            $.ajax({
                url : "ViewArchive",
                data : {"searchString" : name.toString(), "searchType" : type,"searchBy":by },
                type : "POST",
                success : function(msg) {
                }
            });

            name = "";
            type = "";
            by = "";    
        });
    });
    </script>
</html>