Google Map does not work in php
<p>I want to show map of my university but it load for 1 sec and then tell</p>

<p><strong>MissingKeyMapError</strong></p>

<p>and</p>

<p><strong>Sorry! Something went wrong.
This page didn't load Google Maps correctly. See the JavaScript console for technical details.</strong></p>

<p>I use Google Maps JavaScript API and Web browser (javaScript).Hear is my code :</p>

<pre><code>    &lt;script src='https://maps.googleapis.com/maps/api/js?key=AIzaSyDNi7fQreXQ_AvjDEbMBGtBo2XoP5QkxRs'&gt;&lt;/script&gt;
    &lt;div style='overflow:hidden;height:440px;width:700px;'&gt;
        &lt;div id='gmap_canvas' style='height:440px;width:700px;'&gt;&lt;/div&gt;
        &lt;style&gt;#gmap_canvas img {
            max-width: none !important;
            background: none !important
        }       &lt;/style&gt;
    &lt;/div&gt;
    &lt;script type='text/javascript'&gt;
        function init_map() {
            var myOptions = {
                zoom: 14,
                center: new google.maps.LatLng(22.3475365, 91.81233240000006),
                mapTypeId: google.maps.MapTypeId.ROADMAP
                };
            map = new google.maps.Map(document.getElementById('gmap_canvas'), myOptions);
            marker = new google.maps.Marker({
                map: map,
                position: new google.maps.LatLng(22.3475365, 91.81233240000006)
            });
            infowindow = new google.maps.InfoWindow({content: '&lt;strong&gt;University of Chittagong&lt;/strong&gt;&lt;br&gt;Chittagong , Bangladesh&lt;br&gt;'});
            google.maps.event.addListener(marker, 'click', function () {
                infowindow.open(map, marker);
            });
            infowindow.open(map, marker);
        }
            google.maps.event.addDomListener(window, 'load', init_map);
    &lt;/script&gt;
&lt;/head&gt;
</code></pre>

<p>This is my full code . Please help me for my project.</p>