Google map api

map.js

function initialize() {
        var zoom_area_coordinates = document.getElementById("coordinates").value.split(" ")
        var zoom_level = 4;
        if(request_type == "true" && (flash_value == "No Doctor found" || flash_value == "Please enter an address")){

          zoom_level = 4;
        }
        else if(request_type == "true"){

            zoom_level = 13;
        }
        old_zoom = zoom_level;
        current_zoom = zoom_level;

        var myLatlng = new google.maps.LatLng(parseFloat(zoom_area_coordinates[0]), parseFloat(zoom_area_coordinates[1]));
        var myOptions = {
            zoom: zoom_level,
            center: myLatlng,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        }
        //for adding map on the page in DIV which has id as "map" 
        map = new google.maps.Map(document.getElementById("map"), myOptions);
        TestMarker();
    }
    // Function for adding a marker to the page.
    function addMarker(location, clinic_name, dr_id, doctor_clinic_id) {
        marker = new google.maps.Marker({
            position: location,
            map: map,
            doctor_id: dr_id,
            doctor_clinic_id: doctor_clinic_id,
            label: {
                color: 'black'
            },
             title: clinic_name

        });
// infowindow creation
    var content = document.createElement("DIV");
    content.style.width = "absolute";
    content.style.height = "absolute";
    var infowindow = new google.maps.InfoWindow({
         content: content
     });
        (function (marker) {
            google.maps.event.addListener(marker, "click", function (e) {
                $.ajax({
                    url: '/get_doctor_info',
                    data: {
                            id: marker.doctor_id,
                            doctor_clinic_id: marker.doctor_clinic_id
                          }
                })
            });

            google.maps.event.addListener(marker, "mouseover", function(evt) {
                content.innerHTML = marker.getTitle();
                infowindow.open(map, marker);
               $(".gm-style-iw").next("div").hide();// hiding CROSS sign from infowindow
               $(".gm-style-iw").css("text-align","center");
               $(".gm-style-iw").css("width","absolute");
            });
            google.maps.event.addListener(marker, "mouseout", function(evt) {

                infowindow.close(map, marker);
            });
        })(marker);
    }

    function pinSymbol(color) {
        return {
            path: 'M 0,0 C -2,-20 -10,-22 -10,-30 A 10,10 0 1,1 10,-30 C 10,-22 2,-20 0,0 z',
            fillColor: color,
            fillOpacity: 1,
            strokeColor: '#000',
            strokeWeight: 2,
            scale: 2
        };
    }

    // Testing the addMarker function
    function TestMarker() {
       $.ajax({
          url: '/get_clinics',
          data: {
                  is_search: request_type,
                  search_text: document.getElementById("p-code").value,
                  radius: parseInt(document.getElementById("radius").value),
                  search_doctor_type: document.getElementById("search_doctor_type").value
                },
          success: function (res){

            var clinic;
            if(res.length > 0){
              for (var i in res){
                clinic = res[i];
                var doctor_location = new google.maps.LatLng(clinic.latitude, clinic.longitude);
                addMarker(doctor_location, clinic.clinic_name, clinic.doctor_id, clinic.clinic_id);
              }
            clinic = res[0]
            var location = new google.maps.LatLng(clinic.latitude, clinic.longitude);
            map.setCenter(location);
            map.addListener('zoom_changed', function() {
                old_zoom = current_zoom;
                current_zoom = map.getZoom();
                zoomDiff = old_zoom - current_zoom;
                if (zoomDiff > 0)
                    AddMoreMarker();
            });

            }
          }
        })
    }

function AddMoreMarker(){
    $.ajax({
        url: '/add_more_clinics',
        data: {
                is_search: request_type,
                search_text: document.getElementById("p-code").value,
                search_doctor_type: document.getElementById("search_doctor_type").value
              },
          success: function (res){
            if(res.length > 0){
                for (var i in res){
                    var clinic = res[i]
                    var doctor_location = new google.maps.LatLng(clinic.latitude, clinic.longitude);
                    addMarker(doctor_location, clinic.clinic_name, clinic.doctor_id, clinic.clinic_id);
                }

            }
        }
    })
}