Google maps infowindow showing on wrong marker

Question

I have a piece of javascript code where I create markers and attach InfoWindows to them, like this:

for (var i = 0; i < 8; i++) {
    var marker = new google.maps.Marker({
       map: map,
       position: new google.maps.LatLng(lat[i], lng[i]),
       icon: '/static/images/iconsets/gmap/iconb' + (i+1) + '.png',
    });
    var infowindow = new google.maps.InfoWindow({
        content: 'test string'
    });
    google.maps.event.addListener(marker, 'click', function() {
        infowindow.open(map,marker);
    });
}

But when I click one of the markers, the infowindow always shows only on one marker. What am I doing wrong?

Answer 1

There's a very simple solution to your problem, which is to put the loop's code into a function. Your problem is that you overwrite the variable marker , so that when it is accessed in the click event, it uses the latest version of that variable, which is the last marker you added.

So, when you put it into a function, the variable is in a separate namespace and therefore not overwritten. In other words, this should work:

for (var i = 0; i < 8; i++) {
    createMarker(i);
}

function createMarker(i) {
    var marker = new google.maps.Marker({
        map: map,
        position: new google.maps.LatLng(lat, lng),
        icon: '/static/images/iconsets/gmap/iconb' + (i+1) + '.png',
    });
    var infowindow = new google.maps.InfoWindow({
        content: 'test string'
    });
    google.maps.event.addListener(marker, 'click', function() {
        infowindow.open(map,marker);
    });
}

Answer 2

google.maps.event.addListener(Marker, 'click', function() {
    InfoWindow.open(map, this);
});

You shoud use this instead of marker because marker will hold the value of last placed marker.

Answer 3

for (var i = 0; i < 8; i++) {
    var marker = new google.maps.Marker({
       map: map,
       position: new google.maps.LatLng(lat[i], lng[i]),
       icon: '/static/images/iconsets/gmap/iconb' + (i+1) + '.png',
       content: 'test string'
    });
    google.maps.event.addListener(marker, 'click', function() {
        new google.maps.InfoWindow({
            content: this.content
        }).open(map, this);
    });
}

Answer 4

As a new option that was not available 7 years ago:

all modern browsers (which is all browsers supporting ECMAScript 6) support block scoped variables which are defined using the let statement. let initializes a variable inside of a given scope eg inside of a loop whereas var defines variables on global or function level. In your case exchanging the var with let will make sure that each marker is properly initialized as a new variable:

for (var i = 0; i < 8; i++) {
    let marker = new google.maps.Marker({
       map: map,
       position: new google.maps.LatLng(lat[i], lng[i]),
       icon: '/static/images/iconsets/gmap/iconb' + (i+1) + '.png',
    });
    let infowindow = new google.maps.InfoWindow({
        content: 'test string'
    });
    google.maps.event.addListener(marker, 'click', function() {
        infowindow.open(map,marker);
    });
}

Answer 5

Try this:

        // Create a marker for each place.
         marker = new google.maps.Marker({
             map: map,
             icon: icon,
             title: place.name,
             animation: google.maps.Animation.DROP,
             position: place.geometry.location
         });
         var infowindow = new google.maps.InfoWindow({
         content:'<div><strong>' + place.name + '</strong><br>' +
            'Place ID: ' + place.place_id + '<br>' +
            place.formatted_address + '</div>'
            });
        marker.addListener('click', function() {
        infowindow.open(map, this);
        });

Thank you