calling url

Hi all i had done with google login in my application same like facebook. I can logout from facebook using

facebook.logout();

but for google i need call this url

https://accounts.google.com/Logout

so that i can logout form the account and redirected to some page. All this should happen when i click a button here is my code

function signoutbutton(e) {
 
    if (Ti.App.Properties.getString('facebookid')) {
        Ti.App.Properties.removeProperty('facebookid');
        facebook.logout();
        var con = Alloy.createController("index");
    } else if (Ti.App.Properties.getString('googleemail')) {
        Ti.App.Properties.removeProperty('googleemail');
 
        //Ti.Platform.openURL('https://accounts.google.com/Logout');
        var con = Alloy.createController("index");
    } else {
        Ti.App.Properties.removeProperty('userid');
        var con = Alloy.createController("index");
    }
 
};

in the above code i had called it using open url but it is opening the webview in mobile and its not redirected to my index page.pls help me I'm using Titanium version 3.1.3 and platform is android.