Edit in JSFiddle

var param = {
	address: "目黒駅",
	lat: 35.681298,
	lng: 139.7662469,
	zoom: 12,
};

console.log(param);

var zoom = parseInt(param['zoom']);
if (param['address']) {
	var geocoder = new google.maps.Geocoder();
	geocoder.geocode({
		address: param['address']
	}, function(results, status) {
	console.log(status);
		if (status == google.maps.GeocoderStatus.OK) {
			console.log(results[0]);
			var latlng = results[0].geometry.location;

			var map = new google.maps.Map(document.getElementById("map"), {
				zoom: zoom,
				center: latlng,
				mapTypeId: google.maps.MapTypeId.ROADMAP
			});
			
			var marker = new google.maps.Marker({
				position: latlng,
				map: map
			});

			var iw = new google.maps.InfoWindow({
         content: title = results[0].formatted_address,
         size: new google.maps.Size(50, 30)
      });

      google.maps.event.addListener(marker, 'click', function() {
         iw.open(map, marker);
      });
		}
	});

} else if (param['lat'] && param['lng']) {

	var latlng = new google.maps.LatLng(param['lat'],param['lng']);
	var map = new google.maps.Map(document.getElementById("map"), {
		zoom: zoom,
		center: latlng,
		mapTypeId: google.maps.MapTypeId.ROADMAP
	});

	var marker = new google.maps.Marker({
		position: latlng,
		map: map
	});
	
}
<div id="map"></div>
#map {
	width: 100%;
	height: 400px;
}

External resources loaded into this fiddle: