Mapbox swipe example, 1.5.2

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Swipe Layers</title>
  
  <meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no' />
  <script src='//api.tiles.mapbox.com/mapbox.js/v1.5.2/mapbox.js'></script>
  <link href='//api.tiles.mapbox.com/mapbox.js/v1.5.2/mapbox.css' rel='stylesheet' />
  
  <style>
    body { margin:0; padding:0; }
    #map { position:absolute; top:0; bottom:0; width:100%; }
  </style>
</head>
<body>
<style>

#range {
    margin-top: 10px;
    -webkit-appearance: none !important;
    background:rgba(255,255,255,0.7);
    height:15px;
    width: 100%;
    position: absolute;
}

input[type="range"]::-webkit-slider-thumb {
     -webkit-appearance: none;
    background-color: #0000ff;
    border: 2px solid #fff;
    opacity: 0.9;
    width: 20px;
    height: 30px;
}

.leaflet-top .leaflet-control-zoom {
  margin-top: 35px;
}
</style>

<div id='map'></div>
<input id="range" type="range" min="0" max="1.0" step="any" style="width: 100%; position: absolute" />
<script>
    var map = L.mapbox.map('map');

L.mapbox.tileLayer('landplanner.blueprint_btv').addTo(map);
    var overlay = L.mapbox.tileLayer('landplanner.map-yp548gxo').addTo(map);

var range = document.getElementById('range');

function clip() {
        var nw = map.containerPointToLayerPoint([0,0]),
            se = map.containerPointToLayerPoint(map.getSize()),
            clipX = nw.x + (se.x - nw.x) * range.value;

overlay.getContainer().style.clip = 'rect(' + [nw.y, clipX, se.y, nw.x].join('px,') + 'px)';
    }

range['oninput' in range ? 'oninput' : 'onchange'] = clip;
    map.on('move', clip);

map.setView([44.4846, -73.2165], 14);

</script>
</body>
</html>

https://api.tiles.mapbox.com/mapbox.js/v1.5.2/mapbox.js