function SwitchPage(PageNumber)
{
    // Button setzen
    var Page1 = GetElement('Page1');
    var Page2 = GetElement('Page2');
    var Page3 = GetElement('Page3');
    var Page4 = GetElement('Page4');
    var Button1 = GetElement('Button1');
    var Button2 = GetElement('Button2');
    var Button3 = GetElement('Button3');
    var Button4 = GetElement('Button4');
    var PageName = 'Page' + PageNumber;
    var ButtonName = 'Button' + PageNumber;
    Page1.style.display = PageName == 'Page1' ? 'block' : 'none';
    Page2.style.display = PageName == 'Page2' ? 'block' : 'none';
    Page3.style.display = PageName == 'Page3' ? 'block' : 'none';
    Page4.style.display = PageName == 'Page4' ? 'block' : 'none';
    Button1.className = ButtonName == 'Button1' ? 'intro-slide-nav current' : 'intro-slide-nav';
    Button2.className = ButtonName == 'Button2' ? 'intro-slide-nav current' : 'intro-slide-nav';
    Button3.className = ButtonName == 'Button3' ? 'intro-slide-nav current' : 'intro-slide-nav';
    Button4.className = ButtonName == 'Button4' ? 'intro-slide-nav current' : 'intro-slide-nav';
}