Problems with ajax in a WebView

A webView was developed for android where it loads the page of a virtual store of mine in opencart.

The problem occurs in the order ending where it does not display the login or payment screen.

In android Chrome it works normal the completion of the purchase.

apk is this. link

The cod of my webview is below:

package br.com.valvier.appvalbier;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebSettings.PluginState;
import android.webkit.CookieManager;
import android.webkit.WebView;
import android.webkit.WebSettings.RenderPriority;
import android.webkit.WebViewClient;

public class MainActivity extends Activity {


    private WebView mWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        CookieManager.getInstance().setAcceptCookie(true);//Enable Cookies

        mWebView = (WebView) findViewById(R.id.webView1);
        mWebView.getSettings().setJavaScriptEnabled(true);//Enable Java Script
        mWebView.setWebViewClient(new HelloWebViewClient());
        mWebView.loadUrl("http://valbier.com.br/"); //Set Home page
        mWebView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);//Remove ScrollBars
        mWebView.getSettings().setDefaultFontSize(12);//Set Font Size
        mWebView.getSettings().setLoadsImagesAutomatically(true);//Enable Image Loading
        mWebView.getSettings().setPluginState(PluginState.ON);//Enable Flash
        mWebView.getSettings().setRenderPriority(RenderPriority.HIGH); //improves Feedback     on touch
        //mWebView.setBackgroundColor(0x00000000);//Transparent Screen When Loading
        //mWebView.getSettings().setBuiltInZoomControls(true);//Set Zoom Controls
        //mWebView.getSettings().setDisplayZoomControls(false);//Always Hide Zoom     Controlls(Requires Api 11)

        mWebView.getSettings().setAppCacheMaxSize(1024*1024*8);//Set Cache (8mb)
        String appCachePath =     getApplicationContext().getCacheDir().getAbsolutePath();//Set Cache (8mb)
        mWebView.getSettings().setAppCachePath(appCachePath);//Set Cache (8mb)
        mWebView.getSettings().setAllowFileAccess(true);//Set Cache (8mb)
        mWebView.getSettings().setAppCacheEnabled(true);//Set Cache (8mb)
        mWebView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);//Set Cache (8mb)

        mWebView.requestFocus(View.FOCUS_DOWN);//Enable WebView Interaction

        mWebView.setWebViewClient(new WebViewClient() {//Open URL on Error
            public void onReceivedError(WebView view, int errorCode, String description,     String failingUrl) {//Open URL on Error
                //mWebView.loadUrl("http://www.google.com");//Open URL on Error

                mWebView.loadUrl("file:///android_asset/offline.html"); //Show Offline HTML     file or Image on Error
            }
        });
    }

    private class HelloWebViewClient extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView webview, String url)
        {


            webview.loadUrl(url);
            return true;
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {

        if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack())

        {
            mWebView.goBack();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}