public void ReplaceChild( 
   HtmlElement newChild,
   HtmlElement oldChild
)

public static int Execute(Instance instance)
{
    instance.ClearCookie();
 
    Tab tab = instance.MainTab;
    if ((tab.IsVoid) || (tab.IsNull)) return -1;
    if (tab.IsBusy) tab.WaitDownloading();
    tab.Navigate("lessons.zennolab.com");
    if (tab.IsBusy) tab.WaitDownloading();
            
    HtmlElement he = tab.FindElementById("main");
            
    HtmlElement heOld = tab.FindElementById("inputs");
            
    HtmlElement heNew = instance.GetTabByAddress("page").GetDocumentByAddress("0").FindElementByAttribute("a", "href", "http://lessons.zennolab.com/ru/index", "regexp", 0);
            
    he.ReplaceChild(heNew, heOld);
            
    return 0;
}

public static function Execute($instance)
{
    $instance->ClearCookie();
 
    $tab = $instance->MainTab;
    if (($tab->IsVoid) || ($tab->IsNull)) return -1;
    if ($tab->IsBusy) $tab->WaitDownloading();
    $tab->Navigate("lessons.zennolab.com");
    if ($tab->IsBusy) $tab->WaitDownloading();
            
    $he = $tab->FindElementById("main");
            
    $heOld = $tab->FindElementById("inputs");
            
    $heNew = $instance->GetTabByAddress("page")->GetDocumentByAddress("0")->FindElementByAttribute("a", "href", "http://lessons.zennolab.com/ru/index", "regexp", 0);
            
    $he->ReplaceChild($heNew, $heOld);
            
    return 0;
}