To use leaflet you need to first change the loading settings for the API. Since leaflet does not come with a tile set, you need to define your own. It should be noted that utilizing mapquest uses leaflet as the base API.
    <script >
        window.scribblemaps = {
            settings: {
                baseAPI: 'leaflet',
                baseLayerType: "<YourMapTypeID>",
                token: '<Your Mapbox Token>',
                baseLayer: 'https://api.mapbox.com/styles/v1/mapbox/satellite-streets-v9/tiles/256/{z}/{x}/{y}@2x?access_token=<Your Mapbox Token>'
        window.onload = function () {
            var sm = new ScribbleMap(document.getElementById('ScribbleMap'));
    <div id="ScribbleMap" style="width: 730px; height: 500px"></div>
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