Titanium webview proxy

I wanna make webview works with proxy (not using wifi, just mobile ddata). i didnt found any solution yet. How can i set username and password to open that url behind proxy server? i already achieved it using android. And i want to make it cross platform now. Thanks in advance if someone know it and willing to share.

it's just a piece of standard webview without proxy :

var window = Titanium.UI.createWindow();
 
    var webview = Ti.UI.createWebView({
    url: 'http://www.google.com'
 
    });
 
    window.addEventListener('android:back', function(e){
 
    if (webview.canGoBack()) {
        webview.goBack();
    } else {
        peringatan.show();
    }
    return false;
    });
 
    var peringatan = Ti.UI.createAlertDialog();
 
    peringatan.message = 'Exit onCom?';
 
    peringatan.buttonNames = ['Yes','No'];
    peringatan.cancel = 1;
 
    peringatan.addEventListener('click', function(e)
    {
 
    if (e.index == 0) {
        window.close();
    }
 
    });
 
    window.add(peringatan);
    window.add(webview);
    window.open();