function PopUp()
{
if(screen.width==800){

    var URL = "warnung1.html";
    var Name = "popup";
    var Fensteroptionen = "toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0";
    var Breite = 330;
    var Hoehe = 350;
    window.open(URL, 'Name', Fensteroptionen + ',width=' + Breite + ',height=' + Hoehe);
    }

if(screen.width==640){

    var URL = "warnung2.html";
    var Name = "popup";
    var Fensteroptionen = "toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0";
    var Breite = 330;
    var Hoehe = 350;
    window.open(URL, 'Name', Fensteroptionen + ',width=' + Breite + ',height=' + Hoehe);
    }
}