Getting unique constraint error but my values are getting stored in database before even i click on add user button.

I have  3 forms and this is my last form contents. I do display all values correctly. Iam getting an error while this form getting displayed and the error is ";" expected. I have seen there is no error anywhere and it is storing below values in database before even i click "add user" button. i am not able to understand why this is happening.
When i traced the error .Iam getting unique constraint violated. But my values are getting stored. I guess it is trying to do twice. Let me know your ideas..

Thanks.

<form name="Form1" method="post" action="">
<%
String fname = (String) session.getAttribute("MySessionfname");
String lname = (String) session.getAttribute("MySessioninlname");
String mname = (String) session.getAttribute("MySessionmname");
String ssn = (String) session.getAttribute("MySessionssn");

String loginname=request.getParameter("loginname");
String password12=request.getParameter("password");
String email=request.getParameter("email");

String previldge1= request.getParameter("previldge");
String[] previldges= previldge1.split(";");

out.println("<center>");
out.println("<br>"+"<br>"+"<br>");
out.println("YOU ARE ABOUT TO ADD A USER WITH FOLLOWING DETAILS.."+"<br>"+"<br>");
out.println("Firstname="+fname+"<br>");
out.println("Lastname="+lname+"<br>");
out.println("MiddleName="+mname+"<br>");
out.println("SSN="+ssn+"<br>");
out.println("Loginname="+loginname+"<br>");
out.println("Password="+password12+"<br>");
out.println("Email="+email+"<br>");
out.println("<br>"+"<br>"+"<br>");
out.println("NEED TO CHANGE?????"+"<br>");
out.println("CLICK BACK BUTTON....");

out.println("</center>");
%>
  <p>&nbsp;</p>
  <p align="center">
    <input type="submit" name="Submit" value="Add User.." onClick="javascript:onadd();">
  </p>
  <p>&nbsp;</p>
  <p>&nbsp;</p>
  <p>&nbsp;</p>
  <p>&nbsp;</p>
  <p>&nbsp;</p>
 
</form>

<script language=javascript>
<!--
function onadd()
{
<%  

String username = "scott";
String password = "tiger";
String url = "jdbc:odbc:grad_project";
try {
       Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //Loads driver
     Connection con=DriverManager.getConnection(url, username, password);
     Statement stat1=con.createStatement();    
        
 
  String query1= "INSERT INTO users(userid,firstname,lastname,middleinitial,email,login,password)VALUES "+
  "('"+ssn+"','"+fname+"','"+lname+"','"+mname+"','"+email+"','"+loginname+"','"+password12+"')";
  stat1.executeUpdate(query1);
  String query2="";
   Statement stat2=con.createStatement();
 if(previldges.length>0)
 {
for (int intCnt = 0;intCnt < previldges.length; intCnt ++)
{
  query2= "INSERT INTO userspecify(userid,previldge)VALUES ('"+ssn+"','"+previldges[intCnt ]+"')";
  stat2.executeUpdate(query2);
}
}
out.println("Successfully Inserted");
      con.commit();
        con.close();
        }
     
    catch(Exception e)
   {
    out.print(e);
   }    
   
 %>
 
// -->
</script>
</body>
</html>