Question

I have a following extra_context in my views.py.

extra_context = {
    'user': list_user,
    'time': str(list_time),
    'latlng': list_latlng
}

All of the above variables are datatype of python list. Now i want to use these variable in Gmap v3 javascript. I found a following snippet for google map: (posting the main part)

<script type="text/javascript">
var map ;
function initialize() {
var latlng = new google.maps.LatLng(-34.397, 150.644);
var myOptions = {
  zoom: 2,
  center: latlng,
  mapTypeId: google.maps.MapTypeId.TERRAIN 
};

map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

var flightPlanCoordinates = [ {% for ip in latlng %}{{ ip }}{% endfor %}];
for(var i in flightPlanCoordinates){
    var marker = add_marker(flightPlanCoordinates[i][0], flightPlanCoordinates[i][1],"Some title!","html for info box");
    marker.setMap(map);
    }
}

function add_marker(lat,lng,title,box_html) {
var infowindow = new google.maps.InfoWindow({
    content: box_html
});

var marker = new google.maps.Marker({
      position: new google.maps.LatLng(lat,lng),
      map: map,
      title: title
});

google.maps.event.addListener(marker, 'click', function() {
  infowindow.open(map,marker);
});   

return marker;

}

The above code shows a marker accoriding to the latlng list passed from the context. But the problem is occurring at that time when i also tried to pass time and user with the same way. It shows nothing on the Map. By the way i tried with this coide:

var user = [{% for i in user %}{{ i }}{% endfor %}]; 
var timestamp = [{% for y in time %}{{ y }}{% endfor %}];

Is that the right way? I am new in javascript i wrote according the latlng code.

I tried with alert(timestamp). Nothing happens 🙁

Another problem is i have to pass these three parameter to add_marker
java script method. TO do this i have to run three for loop concurrently. Posting the pseudo code:

var user = [{% for i in user %}{{ i }}{% endfor %}]; 
var timestamp = [{% for y in time %}{{ y }}{% endfor %}];
var flightPlanCoordinates = [ {% for ip in latlng %}{{ ip }}{% endfor %}];
for (var in flightPlanCoordinates) and for (a in timestamp) and for(b in user)
{
  var marker = add_marker(flightPlanCoordinates[i][0], flightPlanCoordinates[i][1],b,a);
marker.setMap(map);

Answer 1

You need to define your variables as:

var user = [{% for i in user %}{{ i }}{% if forloop.last %} {%else%} , {%endif%} {% endfor %}];

i.e. add comma between the values in array.