var karte = "land";

 function swapKarte(myplz)
 {
     var b = document.getElementById("showmap");
     if ( karte == "land" ){
       b.src = "showmap.php?plz="+myplz+"&land=ger";
     	 karte = "deutschland";
     	 document.getElementById("lupeMin").style.display = 'none';
     	 document.getElementById("lupeMap24").style.display = 'none';
     	 document.getElementById("lupeLand").style.display = 'inline'; 
     } else {
       b.src = "showmap.php?plz="+myplz;
     	 karte = "land";
     	 document.getElementById("lupeMin").style.display = 'inline';
     	 document.getElementById("lupeMap24").style.display = 'inline';
     	 document.getElementById("lupeLand").style.display = 'none'; 
     	}

 }