how can I select project from dropdown then execute query catching the value of the project selected

I have the follow code using AJAX and JSP pages

admin.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
pageEncoding="ISO-8859-1"%> 
<%@ page import="java.sql.*"%> 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title>index</title>

<script> 
function showState(str){ 
var xmlhttp; 

if (window.XMLHttpRequest) 
{// code for IE7+, Firefox, Chrome, Opera, Safari 
xmlhttp=new XMLHttpRequest(); 
} 
else 
{// code for IE6, IE5 
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); 
} 
xmlhttp.onreadystatechange=function() 
{ 
if (xmlhttp.readyState==4 && xmlhttp.status==200) 
{ 
document.getElementById("domain").innerHTML=xmlhttp.responseText; 
} 
} 
xmlhttp.open("GET","getProjects.jsp?q="+str,true); 
xmlhttp.send(); 
} 
</script> 
</head> 
<body> 

Domain : <select onchange="showState(this.value)"> 
<% 
try { 
Class.forName("oracle.jdbc.OracleDriver"); 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
return; 
} 
Connection connection = null; 
System.setProperty("oracle.net.tns_admin", "C:/oracle/product/10.2.0/client_1/NETWORK/ADMIN");
String dbURL = "jdbc:oracle:thin:@qcd1";
try { 

connection = DriverManager.getConnection(dbURL, "user", "password"); 
} 
catch (SQLException e) { 
e.printStackTrace(); 
return; 
} 

PreparedStatement stmt=null; 
//select from all active domain in ALM
stmt=connection.prepareStatement("SELECT DISTINCT(DOMAIN_ID),DOMAIN_NAME FROM qcsiteadmin_db.projects ORDER BY 2"); 
ResultSet rs=null; 
rs= stmt.executeQuery(); 

while(rs.next()){ 
%> 

<option value="<%=rs.getString(1)%>"><%=rs.getString(2)%></option> 
<% 
} 
%> 
</select> 
<div id="domain"> 
Project  : 
<select> 
<option>Select Domain then Project</option> 
</select> 
</div> 
</body> 
</html> 

The admin.jsp JSP display the list of my domains then other dropdown to select Project(depending of the domain selected) from getProjects.jsp THE CODE BELLOW (query it´s depend of the domain selected )

getProjects.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
pageEncoding="ISO-8859-1"%> 
<%@ page import="java.sql.*"%> 
<%!int i;%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title>Project Page</title> 

<body> 

Project  : 
<select> 

<% 
String str=request.getParameter("q"); 

i=Integer.parseInt(str); 
try { 
Class.forName("oracle.jdbc.OracleDriver"); 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
return; 
} 
Connection connection = null; 
System.setProperty("oracle.net.tns_admin", "C:/oracle/product/10.2.0/client_1/NETWORK/ADMIN");
String dbURL = "jdbc:oracle:thin:@qcd1";
try { 

connection = DriverManager.getConnection(dbURL, "user", "password"); 
} 
catch (SQLException e) { 
e.printStackTrace(); 
return; 
} 

PreparedStatement stmt=null;

stmt=connection.prepareStatement("select DB_NAME,PROJECT_NAME from qcsiteadmin_db.projects where domain_id='"+i+"'order by 2"); 

ResultSet rs=null; 

rs= stmt.executeQuery(); 


while(rs.next()){ 
%> 
<option value="<%=rs.getString(1)%>"><%=rs.getString(2)%></option>

<% 
} 
%> 

</select>
</body> 
</html>

my connection database is working fine , the bellow table must be displaying when Project is selected from dropdown
Note: this is not a static table the table information depends of the value selected please check my page that display the table

getRoles.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
pageEncoding="ISO-8859-1"%> 
<%@ page import="java.sql.*"%> 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<head> 
<link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/static/style.css"/>
</head>

<body>
<div class="CSSTableGenerator">
<table>  
<tr>
                        <td>
                            USERID
                        </td>
                          <td>
                            FULL NAME
                        </td>
                          <td>
                            EMAIL
                        </td>
                          <td>
                            ROLE
                        </td>
</tr>

<% 
try { 
Class.forName("oracle.jdbc.OracleDriver"); 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
return; 
} 
Connection connection = null; 
System.setProperty("oracle.net.tns_admin", "C:/oracle/product/10.2.0/client_1/NETWORK/ADMIN");
String dbURL = "jdbc:oracle:thin:@qcd1";
try { 

connection = DriverManager.getConnection(dbURL, "user", "password"); 
} 
catch (SQLException e) { 
e.printStackTrace(); 
return; 
} 

PreparedStatement stmt=null; 
stmt=connection.prepareStatement("SELECT us_username,full_name,email, GR_Group_Name from energy_energy_plm_db.users, energy_energy_plm_db.Groups,qcsiteadmin_db.users where substr(us_group, gr_group_id + 1, 1) = '1' and us_username=user_name and gr_group_name='TDAdmin' and us_username not like '%admin%' order by 1"); 
ResultSet rs=null; 
rs= stmt.executeQuery(); 

while(rs.next()){ 
%> 

<tr> <td> <%= rs.getString(1) %></td> 
     <td> <%= rs.getString(2) %></td>
     <td> <%= rs.getString(3) %></td>  
     <td> <%= rs.getString(4) %></td> </tr>
<% 
} 
%> 
</table>
</div>
</body> 
</html> 

I don´t know what´s next