Again a new leaflet option to laod a gpx using leaflet.FileLayer.

In head:

<!-- FileLayer -->
<script src="js/FileLayer/leaflet.filelayer.js"></script>

In body:

// FileLayer
L.Control.fileLayerLoad({
        layer: L.geoJson,
        layerOptions: {style: {color:'red'}},
        addToMap: true,
        fileSizeLimit: 3000,
    }).addTo(map);