コツを見つけて、
AutoCompletekeyup入力ノードのイベントによってトリガーされた場合:
display: none;結果がない場合は、結果のドロップダウン リストを非表示にする
また
display結果がある場合、明確なスタイルで結果ドロップダウンリストを表示
document.getElementsByClassName('pac-container')[0]（ネイティブ）または$('.pac-container')（jQuery）でドロップダウンリストを取得できます
したがってdisplay、ドロップダウン リストを「ブロック」に設定し、それを追跡して結果のステータスを検出するだけです。
Google公式サンプルから変更された簡単なサンプル：
<!DOCTYPE html>
<html>
<head>
<title>Google Maps JavaScript API v3 Example: Places Autocomplete</title>
<script src="https://maps.googleapis.com/maps/api/js?sensor=false&libraries=places"
type="text/javascript"></script>
<style type="text/css">
body {
font-family: sans-serif;
font-size: 14px;
}
#map_canvas {
height: 400px;
width: 600px;
margin-top: 0.6em;
}
</style>
<script type="text/javascript">
var ns = {}; // a name space
ns.checktimes = 0; // a couter of check times
// the check function
// @param dropdown: the drop-down list of Places.AutoComplete
// @param msg: the div to show message
ns._doCheck = function (dropdown, msg) {
if (dropdown.style.display == '') {
msg.innerHTML = 'has results? true';
ns.checkTimer = null;
}
else if (dropdown.style.display == 'none') {
msg.innerHTML = 'has results? false';
ns.checkTimer = null;
} else if (ns.checktimes < 20) { // check at most 10 seconds
ns.checktimes++;
ns.checkTimer = setTimeout(function () {
ns._doCheck(dropdown, msg);
}, 500);
}
}
function initialize() {
var mapOptions = {
center: new google.maps.LatLng(-33.8688, 151.2195),
zoom: 13,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map(document.getElementById('map_canvas'),
mapOptions);
var input = document.getElementById('searchTextField');
var autocomplete = new google.maps.places.Autocomplete(input);
autocomplete.bindTo('bounds', map);
var infowindow = new google.maps.InfoWindow();
var marker = new google.maps.Marker({
map: map
});
google.maps.event.addListener(autocomplete, 'place_changed', function() {
infowindow.close();
var place = autocomplete.getPlace();
if (place.geometry.viewport) {
map.fitBounds(place.geometry.viewport);
} else {
map.setCenter(place.geometry.location);
map.setZoom(17); // Why 17? Because it looks good.
}
var image = new google.maps.MarkerImage(
place.icon,
new google.maps.Size(71, 71),
new google.maps.Point(0, 0),
new google.maps.Point(17, 34),
new google.maps.Size(35, 35));
marker.setIcon(image);
marker.setPosition(place.geometry.location);
var address = '';
if (place.address_components) {
address = [(place.address_components[0] &&
place.address_components[0].short_name || ''),
(place.address_components[1] &&
place.address_components[1].short_name || ''),
(place.address_components[2] &&
place.address_components[2].short_name || '')
].join(' ');
}
infowindow.setContent('<div><strong>' + place.name + '</strong><br>' + address);
infowindow.open(map, marker);
// update stored value
ns.oldValue = document.getElementById('searchTextField').value;
});
// Sets a listener on a radio button to change the filter type on Places
// Autocomplete.
function setupClickListener(id, types) {
var radioButton = document.getElementById(id);
google.maps.event.addDomListener(radioButton, 'click', function() {
autocomplete.setTypes(types);
});
}
setupClickListener('changetype-all', []);
setupClickListener('changetype-establishment', ['establishment']);
setupClickListener('changetype-geocode', ['geocode']);
}
// to check whether responsee and has results
function startCheck () {
// the input node
var inp = document.getElementById('searchTextField'),
value = inp.value; // value of input node
if (value && ns.oldValue != value) { // has value and changed, start check
// drop-down list and message div
var dropdown = document.getElementsByClassName('pac-container')[0],
msg = document.getElementById('msg');
// trick! change style to display='block'
dropdown.style.display = 'block';
// update stored value
ns.oldValue = value;
// initiate checktimes
ns.checktimes = 0;
// clear previous timer if exists
if (ns.checkTimer)
clearTimeout (ns.checkTimer);
ns.checkTimer = setTimeout(function () {
ns._doCheck(dropdown, msg);
}, 500);
}
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>
<body>
<div>
<div id="msg">has results? </div>
<input id="searchTextField" type="text" size="50" onkeyup="startCheck();">
<input type="radio" name="type" id="changetype-all" checked="checked">
<label for="changetype-all">All</label>
<input type="radio" name="type" id="changetype-establishment">
<label for="changetype-establishment">Establishments</label>
<input type="radio" name="type" id="changetype-geocode">
<label for="changetype-geocode">Geocodes</lable>
</div>
<div id="map_canvas"></div>
</body>
</html>