using web browser control to implement automatically login in live site. its works only in internet explorer,but its not work in firefox and chrome how to solve this error

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Threading;
using System.Windows.Forms;
using System.Drawing;
using System.IO;

public partial class _Default : System.Web.UI.Page 
{
    static string password = "";

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            txtUsername.Text = "********";
            password = "********";
            for (int i = 0; i < password.Length; i++)
            {
                txtPassword.Text = txtPassword.Text + "*";
            }


            Thread thread = new Thread(delegate()
            {

                using (WebBrowser browser = new WebBrowser())
                {
                    browser.ScrollBarsEnabled = false;
                    browser.AllowNavigation = true;
                    browser.Navigate("URL");
                    browser.Width = 1024;
                    browser.Height = 768;
                    browser.ScriptErrorsSuppressed = true;
                    browser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(DocumentCompleted2);
                    while (browser.ReadyState != WebBrowserReadyState.Complete)
                    {
                        System.Windows.Forms.Application.DoEvents();
                    }
                }
            });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();
            capture();
            Response.Redirect("URL");

        }

    }
    void capture()
    {

        if (password == "********" && txtUsername.Text == "********")
        {

            Thread thread = new Thread(delegate()
            {
                using (WebBrowser browser = new WebBrowser())
                {
                    browser.ScrollBarsEnabled = false;
                    browser.AllowNavigation = true;
                    browser.Navigate("URL");
                    browser.Width = 1024;
                    browser.ScriptErrorsSuppressed = true;
                    browser.Height = 768;
                    browser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(DocumentCompleted);
                    while (browser.ReadyState != WebBrowserReadyState.Complete)
                    {
                        System.Windows.Forms.Application.DoEvents();
                    }
                }
            });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();
        }
        else
        {
            Response.Write("<script>alert('Invalid Username And Password!!!')</script>");
        }
    }


    private void DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        WebBrowser browser1 = sender as WebBrowser;

        HtmlDocument doc = browser1.Document;

        string user = txtUsername.Text.Trim();
        string pass = password;

        doc.GetElementById("username").SetAttribute("value", user);
        doc.GetElementById("passwd").SetAttribute("value", pass);

        //get Button on page and fire its click event
        doc.GetElementById(".save").InvokeMember("Click");

        Thread thread = new Thread(delegate()
        {
            using (WebBrowser browser = new WebBrowser())
            {
                browser.ScrollBarsEnabled = false;
                browser.AllowNavigation = true;
                browser.Navigate("Navigate URL");
                browser.Width = 1024;
                browser.Height = 768;

                browser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(DocumentCompleted1);
                while (browser.ReadyState != WebBrowserReadyState.Complete)
                {
                    System.Windows.Forms.Application.DoEvents();
                }
            }
        });
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        thread.Join();
        //  


    }
    private void DocumentCompleted1(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        WebBrowser browser = sender as WebBrowser;
        using (Bitmap bitmap = new Bitmap(browser.Width, browser.Height))
        {
            browser.DrawToBitmap(bitmap, new Rectangle(0, 0, browser.Width, browser.Height));
            using (MemoryStream stream = new MemoryStream())
            {
                bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                byte[] bytes = stream.ToArray();
                imgScreenShot.Visible = true;
                imgScreenShot.ImageUrl = "data:image/png;base64," + Convert.ToBase64String(bytes);
            }
        }
        // Response.Redirect("URL");

    }

    private void DocumentCompleted2(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        WebBrowser browser = sender as WebBrowser;
        using (Bitmap bitmap = new Bitmap(browser.Width, browser.Height))
        {
            browser.DrawToBitmap(bitmap, new Rectangle(0, 0, browser.Width, browser.Height));
            using (MemoryStream stream = new MemoryStream())
            {
                bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                byte[] bytes = stream.ToArray();
                imgScreenShot.Visible = true;
                imgScreenShot.ImageUrl = "data:image/png;base64," + Convert.ToBase64String(bytes);
            }
        }
    }
}