if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(
function (pos) {
    document.getElementById("lat").value = pos.coords.latitude;
    document.getElementById("lon").value = pos.coords.longitude;
},
function (error) {
switch (error.code) {
case error.POSITION_UNAVAILABLE:
    document.getElementById("lat").value = 999;
    document.getElementById("lon").value = 0;
break;
case error.PERMISSION_DENIED:
    document.getElementById("lat").value = 0;
    document.getElementById("lon").value = 999;
break;
case error.PERMISSION_DENIED_TIMEOUT:
    document.getElementById("lat").value = 999;
    document.getElementById("lon").value = 999;
break;
}
}
);
} else {window.alert("本ブラウザでは現在地周辺検索がご利用いただけません");}