select box and ajax form

Hi Expert,

I'm Joget Starter. I have a question on ajax subform in V4. below in my img.

I create select box with current user, group by department.  

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import org.joget.apps.form.model.*;
import org.joget.apps.form.service.*;
import java.sql.*;
import java.util.*;

Connection con = null;

Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql://localhost:3307/jwdb?characterEncoding=UTF-8", "root", "");

FormRowSet select_user = new FormRowSet();
select_user.setMultiRow(true);

if(!con.isClosed()){
String deptname = "#currentUser.department.name#"; 
PreparedStatement stmt = con.prepareStatement("select u.id, CONCAT(CONCAT(u.firstName, ' '), u.lastName) from dir_user u join dir_employment e on e.userId = u.id join dir_department d on d.id = e.departmentId where d.name = '#currentUser.department.name#' order by firstname asc"); 
ResultSet rs = stmt.executeQuery(); 

FormRow user_row = new FormRow();
user_row.put(FormUtil.PROPERTY_VALUE, "");
user_row.put(FormUtil.PROPERTY_LABEL, " - Select - ");
select_user.add(user_row);

while (rs.next()){
FormRow user_row = new FormRow();
user_row.put(FormUtil.PROPERTY_VALUE, rs.getString(1));
user_row.put(FormUtil.PROPERTY_LABEL, rs.getString(2));
select_user.add(user_row);
}
}

return select_user;

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After selected user, my ajaxform show user detail.

how can i get select box value in bean shell form builder?

i saw V5

http://dev.joget.org/community/display/KBv5/AJAX+Subform

how i can make it. Thank you.