Gtk3::WebKit

test.pl

use v5.16;
use Gtk3 -init;
use Gtk3::WebKit;
my ($file, $url, $wait) = ('out.png', 'http://yandex.ru');

(my $view = Gtk3::WebKit::WebView->new)->set_transparent(Glib::TRUE);
(my $window = Gtk3::OffscreenWindow->new)->add($view);
$view->signal_connect('notify::load-status' => sub { if ($view->get_uri && $view->get_load_status eq 'finished') {
    Glib::Timeout->add( $wait // 50, sub { 
        my $dom = $view->get_dom_document;
        $dom->get_elements_by_class_name('b-head-tabs__tab')->item(3)->get_style->set_property( border=>'3px solid red', '' );
        $view->get_snapshot->write_to_png($file); 
        exit 0 } ) } } );
$window->show_all;
$view->load_uri($url);
Gtk3->main;