openstreetmap-website/app/assets/javascripts/index/browse.js

OSM.initializeBrowse = function (map) {
  var browseBounds;
  var dataLayer = map.dataLayer;

  dataLayer.setStyle({
    way: {
      weight: 3,
      color: "#000000",
      opacity: 0.4
    },
    area: {
      weight: 3,
      color: "#ff0000"
    },
    node: {
      color: "#00ff00"
    }
  });

  dataLayer.isWayArea = function () {
    return false;
  };

  dataLayer.on("click", function (e) {
    onSelect(e.layer);
  });

  map.on("layeradd", function (e) {
    if (e.layer === dataLayer) {
      map.on("moveend", updateData);
      updateData();
    }
  });

  map.on("layerremove", function (e) {
    if (e.layer === dataLayer) {
      map.off("moveend", updateData);
      $("#browse_status").empty();
    }
  });

  function updateData() {
    var bounds = map.getBounds();
    if (!browseBounds || !browseBounds.contains(bounds)) {
      getData();
    }
  }

  function displayFeatureWarning(count, limit, add, cancel) {
    $("#browse_status").html(
      $("<div>")
        .append(
          $("<h2>")
            .text(I18n.t("browse.start_rjs.load_data"))
            .prepend($("<span class='icon close'></span>").click(cancel)))
        .append(
          $("<div>")
            .append(
              $("<p class='alert alert-warning clearfix'></p>")
                .text(I18n.t("browse.start_rjs.feature_warning", { num_features: count, max_features: limit })))
            .append(
              $("<input type='submit' class='btn btn-primary'>")
                .val(I18n.t("browse.start_rjs.load_data"))
                .click(add))));
  }

  var dataLoader;

  function getData() {
    var bounds = map.getBounds();
    var url = "/api/" + OSM.API_VERSION + "/map?bbox=" + bounds.toBBoxString();

    /*
     * Modern browsers are quite happy showing far more than 100 features in
     * the data browser, so increase the limit to 2000 by default, but keep
     * it restricted to 500 for IE8 and 100 for older IEs.
     */
    var maxFeatures = 2000;

    /*@cc_on
      if (navigator.appVersion < 8) {
        maxFeatures = 100;
      } else if (navigator.appVersion < 9) {
        maxFeatures = 500;
      }
    @*/

    if (dataLoader) dataLoader.abort();

    dataLoader = $.ajax({
      url: url,
      success: function (xml) {
        dataLayer.clearLayers();

        var features = dataLayer.buildFeatures(xml);

        function addFeatures() {
          $("#browse_status").empty();
          dataLayer.addData(features);
          browseBounds = bounds;
        }

        function cancelAddFeatures() {
          $("#browse_status").empty();
        }

        if (features.length < maxFeatures) {
          addFeatures();
        } else {
          displayFeatureWarning(features.length, maxFeatures, addFeatures, cancelAddFeatures);
        }

        dataLoader = null;
      }
    });
  }

  function onSelect(layer) {
    OSM.router.route("/" + layer.feature.type + "/" + layer.feature.id);
  }
};