Android: insert data into html input

I have a problem with inserting saved data from Android app into html input. Site is loaded into WebView component, so i have access to my site in my app, but i still can't insert saved data (from previous activities) into html text input... I have found some code - webview.loadUrl("javascript:document.getElementById('pass_id').value = 'y2Yb2q2ckM'"); and tried use code from this link - https://stackoverflow.com/a/12450427/1196540 but those codes does not worked for me... Can anyone give advice or help me with my problem?

UPD and here is my web-form:

<form method="post" action="">
<input name="pass" id="pass_id" type="password" autocomplete="off" value="" class="keyboardInput" onkeyup="$('#warn2').show();"/>

UPD 2

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_browser_screen);

    Intent intent = getIntent();
    CLIENT_ID = intent.getExtras().getString("CLIENT_ID");
    lang = intent.getExtras().getString("LANGUAGE");
    CLIENT_PWD = intent.getExtras().getString("PASSWORD");

    if (lang.equals("English"))
        url = link.getEng();
    else if (lang.equals("Russian"))
        url = link.getRussian();
    else if (lang.equals("Dutch(German)"))
        url = link.getDeutch();
    else if (lang.equals("French"))
        url = link.getFrance();
    else if (lang.equals("Italian"))
        url = link.getItalian();
    else if (lang.equals("Spanish"))
        url = link.getSpanish();

    //go to the website
    WebView webview = new WebView(this);
    setContentView(webview);
    WebSettings webSettings = webview.getSettings();
    webSettings.setJavaScriptEnabled(true);

    webview.setWebViewClient(new WebViewClient());

    data = "client_id=" + CLIENT_ID;
    webview.postUrl(url, EncodingUtils.getBytes(data, "base64"));

    //insert pass
    //webview.loadUrl("javascript:document.getElementById('pass_id').value = 'y2Yb2q2ckM'");
    webview.loadUrl("javascript:document.getElementById('pass_id').focus()");
}