地理位置搜索框未显示建议

Question

我已经在我的页面中安装了这个地理位置api来搜索用户的当前位置，然后显示到目的地的路线，但我还希望它在用户在搜索框中输入目的地时显示建议

<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?     sensor=false"></script>  
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?  key=AIzaSyC6v5-2uaq_wusHDktM9ILcqIrlPtnZgEk&sensor=false">  
</script>  
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyC6v5-2uaq_wusHDktM9ILcqIrlPtnZgEk&libraries=places&callback=initAutocomplete"
     async defer></script>
<script>
function initAutocomplete() {
var map = new google.maps.Map(document.getElementById("MyMapLOC"),  mapOptions);
});
var input = document.getElementById('txtDestination');
    var searchBox = new google.maps.places.SearchBox(input);
    map.controls[google.maps.ControlPosition.TOP_LEFT].push(input);
}
</script> 
<%--Getting User Current Location--%>  

<script type="text/javascript">  
    if (navigator.geolocation) {  
        navigator.geolocation.getCurrentPosition(success);  
    } else {  
        alert("There is Some Problem on your current browser to get Geo Location!");  
    }  

    function success(position) {  
        var lat = position.coords.latitude;  
        var long = position.coords.longitude;  
        var city = position.coords.locality;  
        var LatLng = new google.maps.LatLng(lat, long);  
        var mapOptions = {  
            center: LatLng,  
            zoom: 12,  
            mapTypeId: google.maps.MapTypeId.ROADMAP  
        };  

        var map = new google.maps.Map(document.getElementById("MyMapLOC"), mapOptions);  
        var marker = new google.maps.Marker({  
            position: LatLng,  
            title: "<div style = 'height:60px;width:200px'><b>Your location:      </b><br />Latitude: "  
                        + lat + +"<br />Longitude: " + long  
        });  

        marker.setMap(map);  
        var getInfoWindow = new google.maps.InfoWindow({ content: "<b>Your  Current Location</b><br/> Latitude:" +  
                                lat + "<br /> Longitude:" + long + ""  
        });  
        getInfoWindow.open(map, marker);  
    }  
</script>  

<%--Getting Route Direction From User Current Location to Destination--%>  

<script type="text/javascript">  
    function SearchRoute() {  
        document.getElementById("MyMapLOC").style.display = 'none';  

        var markers = new Array();  
        var myLatLng;  

        //Find the current location of the user.  
        if (navigator.geolocation) {  
            navigator.geolocation.getCurrentPosition(function(p) {  
                var myLatLng = new google.maps.LatLng(p.coords.latitude, p.coords.longitude);  
                var m = {};  
                m.title = "Your Current Location";  
                m.lat = p.coords.latitude;  
                m.lng = p.coords.longitude;  
                markers.push(m);  

                //Find Destination address location.  
                var address = document.getElementById("txtDestination").value;  
                var geocoder = new google.maps.Geocoder();  
                geocoder.geocode({ 'address': address }, function(results, status) {  
                    if (status == google.maps.GeocoderStatus.OK) {  
                        m = {};  
                        m.title = address;  
                        m.lat = results[0].geometry.location.lat();  
                        m.lng = results[0].geometry.location.lng();  
                        markers.push(m);  
                        var mapOptions = {  
                            center: myLatLng,  
                            zoom: 4,  
                            mapTypeId: google.maps.MapTypeId.ROADMAP  
                        };  
                        var map = new google.maps.Map(document.getElementById("MapRoute"), mapOptions);  
                        var infoWindow = new google.maps.InfoWindow();  
                        var lat_lng = new Array();  
                        var latlngbounds = new google.maps.LatLngBounds();  

                        for (i = 0; i < markers.length; i++) {  
                            var data = markers[i];  
                            var myLatlng = new google.maps.LatLng(data.lat, data.lng);  
                            lat_lng.push(myLatlng);  
                            var marker = new google.maps.Marker({  
                                position: myLatlng,  
                                map: map,  
                                title: data.title  
                            });  
                            latlngbounds.extend(marker.position);  
                            (function(marker, data) {  
                                google.maps.event.addListener(marker, "click", function(e) {  
                                    infoWindow.setContent(data.title);  
                                    infoWindow.open(map, marker);  
                                });  
                            })(marker, data);  
                        }  
                        map.setCenter(latlngbounds.getCenter());  
                        map.fitBounds(latlngbounds);  

                        //***********ROUTING****************//  

                        //Initialize the Path Array.  
                        var path = new google.maps.MVCArray();  

                        //Getting the Direction Service.  
                        var service = new google.maps.DirectionsService();  

                        //Set the Path Stroke Color.  
                        var poly = new google.maps.Polyline({ map: map, strokeColor: '#4986E7' });  

                        //Loop and Draw Path Route between the Points on MAP.  
                        for (var i = 0; i < lat_lng.length; i++) {  
                            if ((i + 1) < lat_lng.length) {  
                                var src = lat_lng[i];  
                                var des = lat_lng[i + 1];  
                                path.push(src);  
                                poly.setPath(path);  
                                service.route({  
                                    origin: src,  
                                    destination: des,  
                                    travelMode: google.maps.DirectionsTravelMode.DRIVING  
                                }, function(result, status) {  
                                    if (status == google.maps.DirectionsStatus.OK) {  
                                        for (var i = 0, len = result.routes[0].overview_path.length; i < len; i++) {  
                                            path.push(result.routes[0].overview_path[i]);  
                                        }  
                                    } else {  
                                        alert("Invalid location.");  
                                        window.location.href = window.location.href;  
                                    }  
                                });  
                            }  
                        }  
                    } else {  
                        alert("Request failed.")  
                    }  
                });  

            });  
        }  
        else {  
            alert('Some Problem in getting Geo Location.');  
            return;  
        }  
    }  
</script>