ol3 Demo3 ----加载gpx，geojson格式的数据

      var gpx = new ol.layer.Vector({
        title:‘GPX‘,
        source: new ol.source.Vector({
          url: ‘cycling-vietnam-without-baggage.gpx‘, 
          format: new ol.format.GPX()
        }),
        style: function(feature) {
          return style[feature.getGeometry().getType()];
        }
      });

 var vectorLayer = new ol.layer.Vector({
        source: new ol.source.Vector({
          url: ‘test.geojson‘,
          format: new ol.format.GeoJSON()
        }),
        style: function(feature) {
          style.getText().setText(feature.get(‘name‘));
          return style;
        }
      });