map.html

<!DOCTYPE html>
<html>
   <head>
      <title>Leaflet Quick Start Guide Example</title>
      <meta charset="utf-8" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css" />
      <script type="text/javascript" src="qrc:///qtwebchannel/qwebchannel.js"></script>
   </head>
   <body onload="initialize()" style="margin:0;padding:0;height:100%;width:100%">
      <div id="mapid" style="height:100%; width:100%;position:absolute;"></div>
      <script src="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js"></script>
      <script>
// Initialise web page
function initialize() {
    initialize_qt(function() {
        // connect to a signal
        qmlLeaflet.setCenterMap.connect(function(latitude, longitude) {
            if (typeof qmlLeaflet !== 'undefined') {
                centerMap(qmlLeaflet.latitude, qmlLeaflet.longitude);
            }
        });
    });
}

// Initialise connection to QT C++
function initialize_qt(callback) {
    if (typeof qt != 'undefined') new QWebChannel(qt.webChannelTransport, function(channel) {
        // To make the object known globally, assign it to the window object, i.e.:
        window.qmlLeaflet = channel.objects.qmlLeaflet;
        callback();
    });
}

// function, can be called from C++ or from Javascript
function centerMap(lat, lng) {
    if (map.getCenter().lat != lat && map.getCenter().lng != lng) {
        map.setView([lat, lng], map.zoom);
    }
}

var map = L.map('mapid').setView([51.505, -0.09], 13);

L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token=pk.eyJ1IjoibWFwYm94IiwiYSI6ImNpandmbXliNDBjZWd2M2x6bDk3c2ZtOTkifQ._QA7i5Mpkd_m30IGElHziw', {
    maxZoom: 18,
    attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
        '<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
        'Imagery © <a href="http://mapbox.com">Mapbox</a>',
    id: 'mapbox.streets'
}).addTo(map);

      </script>
   </body>
</html>