地图未加载到HTML页面中

我有一个要加载到HTML页面的地图，该地图的文件位于app文件夹中，但不加载。这是插入地图的地方的代码

<!-- Contact section start -->
    <div id="contact" class="contact">
        <div class="section ">
            <div class="container">
                <div class="title">
                    <h1>Contact Us</h1>
                    <p>Duis mollis placerat quam, eget laoreet tellus tempor eu. Quisque dapibus in purus in dignissim.</p>
                </div>
            </div>
            <div class="map-wrapper">
                <div class="map-canvas" id="map-canvas">Loading map...</div>
                <div class="container">
                    <div class="row-fluid">
                        <div class="span5 contact-form centered">
                            <h3>Say Hello</h3>
                            <div id="successSend" class="alert alert-success invisible">
                                <strong>Well done!</strong>Your message has been sent.</div>
                            <div id="errorSend" class="alert alert-error invisible">There was an error.</div>
                            <form id="contact-form" action="php/mail.php">
                                <div class="control-group">
                                    <div class="controls">
                                        <input class="span12" type="text" id="name" name="name" placeholder="* Your name..." />
                                        <div class="error left-align" id="err-name">Please enter name.</div>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <div class="controls">
                                        <input class="span12" type="email" name="email" id="email" placeholder="* Your email..." />
                                        <div class="error left-align" id="err-email">Please enter valid email adress.</div>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <div class="controls">
                                        <textarea class="span12" name="comment" id="comment" placeholder="* Comments..."></textarea>
                                        <div class="error left-align" id="err-comment">Please enter your comment.</div>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <div class="controls">
                                        <button id="send-mail" class="message-btn">Send message</button>
                                    </div>
                                </div>
                            </form>
                        </div>
                    </div>
                </div>
            </div>
            <div class="container">
                <div class="span9 center contact-info">
                    <p style="color:black;">123 Fifth Avenue, 12th,Belgrade,SRB 11000</p>
                    <p class="info-mail">[email protected]</p>
                    <p style="color:black;">+11 234 567 890</p>
                    <p style="color:black;">+11 286 543 850</p>

                </div>

            </div>
        </div>
    </div>
    <!-- Contact section edn -->

这是js文件，其中包含加载地图所需的所有代码。

    //Initialize google map for contact setion with your location.

function initializeMap() {

var lat = '44.8164056'; //Set your latitude.
var lon = '20.46090424'; //Set your longitude.

var centerLon = lon - 0.0105;

var myOptions = {
    scrollwheel: false,
    draggable: false,
    disableDefaultUI: true,
    center: new google.maps.LatLng(lat, centerLon),
    zoom: 15,
    mapTypeId: google.maps.MapTypeId.ROADMAP
};

//Bind map to elemet with id map-canvas
var map = new google.maps.Map(document.getElementById('map-canvas'), myOptions);
var marker = new google.maps.Marker({
    map: map,
    position: new google.maps.LatLng(lat, lon),
});

var infowindow = new google.maps.InfoWindow();

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

infowindow.open(map, marker);
google.maps.event.addDomListener(window, 'load', initializeMap);

}

我看到其他人也遇到类似的问题，但是他们通过在标记区域中键入optimized：false来解决了这个问题，但对我来说仍然无法正常工作。