function setVisibility() {
        var val = document.myForm.control.options[document.myForm.control.selectedIndex].value;
        document.getElementById("landLayer").style.display = "none";
        document.getElementById("landLayer2").style.display = "none";
        document.getElementById("landLayer3").style.display = "none";
        document.getElementById("landLayer5").style.display = "none";
        document.getElementById("landLayer6").style.display = "none";
        document.getElementById("landLayer7").style.display = "none";
        document.getElementById("landLayer8").style.display = "none";
        document.getElementById("landLayer9").style.display = "none";
        document.getElementById("landLayer10").style.display = "none";
        document.getElementById("landLayer11").style.display = "none";
        document.getElementById("landLayer12").style.display = "none";
        document.getElementById("landLayer13").style.display = "none";
        document.getElementById("landLayer14").style.display = "none";
        document.getElementById("landLayer15").style.display = "none";
        document.getElementById("landLayer16").style.display = "none";
        document.getElementById("landLayer17").style.display = "none";
        document.getElementById("landLayer18").style.display = "none";
        document.getElementById("landLayer19").style.display = "none";
        document.getElementById("landLayer20").style.display = "none";
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        document.getElementById("landLayer22").style.display = "none";
        document.getElementById("landLayer23").style.display = "none";
        document.getElementById("landLayer24").style.display = "none";
        document.getElementById("landLayer25").style.display = "none";
        document.getElementById("landLayer26").style.display = "none";
        document.getElementById("landLayer27").style.display = "none";
        document.getElementById("landLayer28").style.display = "none";
        document.getElementById("landLayer29").style.display = "none";
        document.getElementById("landLayer30").style.display = "none";
        document.getElementById("landLayer31").style.display = "none";
        document.getElementById("landLayer32").style.display = "none";
        document.getElementById("landLayer33").style.display = "none";
        document.getElementById("landLayer34").style.display = "none";
        document.getElementById("landLayer35").style.display = "none";
        document.getElementById("landLayer36").style.display = "none";
        document.getElementById("landLayer37").style.display = "none";
        document.getElementById("landLayer38").style.display = "none";
        document.getElementById("landLayer39").style.display = "none";
        document.getElementById("landLayer40").style.display = "none";
        document.getElementById("landLayer41").style.display = "none";
        document.getElementById("landLayer42").style.display = "none";
        document.getElementById("landLayer43").style.display = "none";
        document.getElementById("landLayer44").style.display = "none";
        document.getElementById("landLayer45").style.display = "none";
        document.getElementById("landLayer50").style.display = "none";
        document.getElementById("landLayer51").style.display = "none";
        document.getElementById("landLayer52").style.display = "none";
        document.getElementById("landLayer53").style.display = "none";
        document.getElementById("landLayer54").style.display = "none";
        if (val == 0) {
			// Alle einblenden:
            document.getElementById("landLayer").style.display = "block";
            document.getElementById("landLayer2").style.display = "block";
            document.getElementById("landLayer3").style.display = "block";
            document.getElementById("landLayer5").style.display = "block";
            document.getElementById("landLayer6").style.display = "block";
            document.getElementById("landLayer7").style.display = "block";
            document.getElementById("landLayer8").style.display = "block";
            document.getElementById("landLayer9").style.display = "block";
            document.getElementById("landLayer10").style.display = "block";
            document.getElementById("landLayer11").style.display = "block";
            document.getElementById("landLayer12").style.display = "block";
            document.getElementById("landLayer13").style.display = "block";
            document.getElementById("landLayer14").style.display = "block";
            document.getElementById("landLayer15").style.display = "block";
            document.getElementById("landLayer16").style.display = "block";
            document.getElementById("landLayer17").style.display = "block";
            document.getElementById("landLayer18").style.display = "block";
            document.getElementById("landLayer19").style.display = "block";
            document.getElementById("landLayer20").style.display = "block";
            document.getElementById("landLayer21").style.display = "block";
            document.getElementById("landLayer22").style.display = "block";
            document.getElementById("landLayer23").style.display = "block";
            document.getElementById("landLayer24").style.display = "block";
            document.getElementById("landLayer25").style.display = "block";
            document.getElementById("landLayer26").style.display = "block";
            document.getElementById("landLayer27").style.display = "block";
            document.getElementById("landLayer28").style.display = "block";
            document.getElementById("landLayer29").style.display = "block";
            document.getElementById("landLayer30").style.display = "block";
            document.getElementById("landLayer31").style.display = "block";
            document.getElementById("landLayer32").style.display = "block";
            document.getElementById("landLayer33").style.display = "block";
            document.getElementById("landLayer34").style.display = "block";
            document.getElementById("landLayer35").style.display = "block";
            document.getElementById("landLayer36").style.display = "block";
            document.getElementById("landLayer37").style.display = "block";
            document.getElementById("landLayer38").style.display = "block";
            document.getElementById("landLayer39").style.display = "block";
            document.getElementById("landLayer40").style.display = "block";
            document.getElementById("landLayer41").style.display = "block";
            document.getElementById("landLayer42").style.display = "block";
            document.getElementById("landLayer43").style.display = "block";
            document.getElementById("landLayer44").style.display = "block";
            document.getElementById("landLayer45").style.display = "block";
            document.getElementById("landLayer50").style.display = "block";
            document.getElementById("landLayer51").style.display = "block";
            document.getElementById("landLayer52").style.display = "block";
            document.getElementById("landLayer53").style.display = "block";
            document.getElementById("landLayer54").style.display = "block";
        } else if (val == 1) {
            document.getElementById("landLayer").style.display = "block";
        } else if (val == 2) {
            document.getElementById("landLayer2").style.display = "block";
        } else if (val == 3) {
            document.getElementById("landLayer3").style.display = "block";
        } else if (val == 5) {
            document.getElementById("landLayer5").style.display = "block";
        } else if (val == 6) {
            document.getElementById("landLayer6").style.display = "block";
        } else if (val == 7) {
            document.getElementById("landLayer7").style.display = "block";
        } else if (val == 8) {
            document.getElementById("landLayer8").style.display = "block";
        } else if (val == 9) {
            document.getElementById("landLayer9").style.display = "block";
        } else if (val == 10) {
            document.getElementById("landLayer10").style.display = "block";
        } else if (val == 11) {
            document.getElementById("landLayer11").style.display = "block";
        } else if (val == 12) {
            document.getElementById("landLayer12").style.display = "block";
        } else if (val == 13) {
            document.getElementById("landLayer13").style.display = "block";
        } else if (val == 14) {
            document.getElementById("landLayer14").style.display = "block";
        } else if (val == 15) {
            document.getElementById("landLayer15").style.display = "block";
        } else if (val == 16) {
            document.getElementById("landLayer16").style.display = "block";
        } else if (val == 17) {
            document.getElementById("landLayer17").style.display = "block";
        } else if (val == 18) {
            document.getElementById("landLayer18").style.display = "block";
        } else if (val == 19) {
            document.getElementById("landLayer19").style.display = "block";
        } else if (val == 20) {
            document.getElementById("landLayer20").style.display = "block";
        } else if (val == 21) {
            document.getElementById("landLayer21").style.display = "block";
        } else if (val == 22) {
            document.getElementById("landLayer22").style.display = "block";
        } else if (val == 23) {
            document.getElementById("landLayer23").style.display = "block";
        } else if (val == 24) {
            document.getElementById("landLayer24").style.display = "block";
        } else if (val == 25) {
            document.getElementById("landLayer25").style.display = "block";
        } else if (val == 26) {
            document.getElementById("landLayer26").style.display = "block";
        } else if (val == 27) {
            document.getElementById("landLayer27").style.display = "block";
        } else if (val == 28) {
            document.getElementById("landLayer28").style.display = "block";
        } else if (val == 29) {
            document.getElementById("landLayer29").style.display = "block";
        } else if (val == 30) {
            document.getElementById("landLayer30").style.display = "block";
        } else if (val == 31) {
            document.getElementById("landLayer31").style.display = "block";
        } else if (val == 32) {
            document.getElementById("landLayer32").style.display = "block";
        } else if (val == 33) {
            document.getElementById("landLayer33").style.display = "block";
        } else if (val == 34) {
            document.getElementById("landLayer34").style.display = "block";
        } else if (val == 35) {
            document.getElementById("landLayer35").style.display = "block";
        } else if (val == 36) {
            document.getElementById("landLayer36").style.display = "block";
        } else if (val == 37) {
            document.getElementById("landLayer37").style.display = "block";
        } else if (val == 38) {
            document.getElementById("landLayer38").style.display = "block";
        } else if (val == 39) {
            document.getElementById("landLayer39").style.display = "block";
        } else if (val == 40) {
            document.getElementById("landLayer40").style.display = "block";
        } else if (val == 41) {
            document.getElementById("landLayer41").style.display = "block";
        } else if (val == 42) {
            document.getElementById("landLayer42").style.display = "block";
        } else if (val == 43) {
            document.getElementById("landLayer43").style.display = "block";
        } else if (val == 44) {
            document.getElementById("landLayer44").style.display = "block";
        } else if (val == 45) {
            document.getElementById("landLayer45").style.display = "block";
        } else if (val == 50) {
            document.getElementById("landLayer50").style.display = "block";
        } else if (val == 51) {
            document.getElementById("landLayer51").style.display = "block";
        } else if (val == 52) {
            document.getElementById("landLayer52").style.display = "block";
        } else if (val == 53) {
            document.getElementById("landLayer53").style.display = "block";
        } else if (val == 54) {
            document.getElementById("landLayer53").style.display = "block";
        }
    }