How to handle Ajax based applications (How manay ways we can able to select drop down values )

How to handle Ajax based applications (How manay ways we can able to select drop down values )
package automation;

import static org.testng.Assert.assertEquals;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.ie.InternetExplorerDriver;
import org.openqa.selenium.support.ui.Select;
import org.testng.annotations.*;

public class AjaxDemo {
    WebDriver d;
   
    @Test
    public void testAjax() throws Exception
    {
        //Load the web page
        d.get("http://www.veethi.com/places/india_banks-ifsc-micr-codes.html");
        assertEquals("Bank IFSC Codes, MICR Codes: Find IFSC, MICR Codes for Major Banks in India",d.getTitle());
        //Select Bank
        Select bank=new Select(d.findElement(By.id("selBank")));
        bank.selectByIndex(4);
        //Select State
        Select state=new Select(d.findElement(By.id("selState")));
        state.selectByVisibleText("Andhra Pradesh");
        //Select city
        Select city=new Select(d.findElement(By.id("selCity")));
        city.selectByVisibleText("Hyderabad");
        //Select Branch
        Select branch=new Select(d.findElement(By.id("selBranch")));
        branch.selectByVisibleText("Sanjeeva Reddy Nagar");
       
        Thread.sleep(4000);
       
    }
   
       
    @BeforeMethod
    public void setUp()
    {
        //Launch browser
        d=new FirefoxDriver();
               d.manage().window().maximize();
        d.manage().timeouts().implicitlyWait(30,TimeUnit.SECONDS);
    }
    @AfterMethod
    public void tearDown()
    {
        //Close browser
        d.quit();
    }


}