Get google.maps.Map instance from a HTMLElement

Question

I have an existing map on a page. I can select that element using something along the lines of document.getElementById() to get the HTMLElement javascript object. Is it possible

Answer 1

You can get google.maps.Map object from DOM Element, with a slight trick.

When you initialize map object, you need to store the object on element's data attribute.

Example:

$.fn.googleMap = function (options) {
    var _this = this;

    var settings = $.extend({}, {
        zoom: 5,
        centerLat: 0,
        centerLon: 0
    }, options);

    this.initialize = function () {
        var mapOptions = {
            zoom: settings.zoom
        };

        var map = new google.maps.Map(_this.get(0), mapOptions);
        // do anything with your map object here,
        // eg: centering map, adding markers' events

        /********************************************
         * This is the trick!
         * set map object to element's data attribute
         ********************************************/
        _this.data('map', map);

        return _this;
    };
    // ... more methods

    return this;
};

After you define a map element, eg:

var mapCanvas = $('#map-canvas');
var map = mapCanvas.googleMap({
    zoom: 5,
    centerLat: 0,
    centerLong: 0
});
// ... add some pre-load initiation here, eg: add some markers
// then initialize map
map.initialize();

you can then get the map object later on by using element's ID, eg:

var mapCanvas = $('#map-canvas');
$('.location').on('click', function () {
    // google map takes time to load, so it's better to get
    // the data after map is rendered completely
    var map = mapCanvas.data("map");
    if (map) {
        map.panTo(new google.maps.LatLng(
            $(this).data('latitude'),
            $(this).data('longitude')
            ));
    }
});

By using this method, you can have multiple maps with different behaviors on a page.