Question

I load the markers and polylines from a ajax page , each request data shown on index page , now I want to clear data (markers,polylines,…) before get new data from ajaxPage

Index Page:

var gmarkers = []; 
var map = null;
function initialize() {
  var myOptions = {
    zoom: 15,
    center: new google.maps.LatLng(35, 53),
    // mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU},
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }

  map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
  google.maps.event.addListener(map, 'click', function() {
        infowindow.close();
        });

}

var infowindow = new google.maps.InfoWindow(
  { 
    size: new google.maps.Size(150,50)
  });

function myclick(i) {
  google.maps.event.trigger(gmarkers[i], "click");
}

function createMarker(latlng, name, html) {
    var contentString = html;
    var marker = new google.maps.Marker({
        position: latlng,
        map: map,
        zIndex: Math.round(latlng.lat()*-100000)<<5
        });

    google.maps.event.addListener(marker, 'click', function() {
        infowindow.setContent(contentString); 
        infowindow.open(map,marker);
        });
    // save the info we need to use later for the side_bar
    gmarkers.push(marker);
}

Ajax Page(record2.php):

var polylines = [];

var beaches = [
    ['Bondi Beach',10,15, 4],
    ['Coogee Beach',11,16, 5],
    ['Cronulla Beach',13,15, 3],
    ['Manly Beach',13,17, 2],
    ['Maroubra Beach',12,10, 1]
];

for (var i = 0; i < beaches.length; i++) {
    var beach = beaches[i];
    var myLatLng = new google.maps.LatLng(beach[1], beach[2]);
    // var polylines = new google.maps.LatLng(beach[1], beach[2]);
    polylines.push(new google.maps.LatLng(beach[1], beach[2]));

    var marker = createMarker(myLatLng,"This place",beach[0])
}

var routes = new google.maps.Polyline({
    path: polylines,
    strokeColor: "#FF0000",
    strokeOpacity: 0.6,
    strokeWeight: 4
});

routes.setMap(map);

Question: simple way to clear polylines , markers and etc before load new data from ajax page ?

/— EDIT —/
I check the answer of Google Maps API v3: How to remove all markers? but just first request from requested page was response , next requests will not work , I think I wrong add a clear map function

Call AjaxPage From Index:

$(document).ready(function(){
     $('#loader').hide();

        $("#search_button").click(function() {

            $('#loader').fadeIn(200);
            $('#login_group').slideUp(200);
            $.post("record2.php", {
                time: $('#login_username').val()

            }, function(response){
                setTimeout("finishAjax('login_group', '"+escape(response)+"')", 200);
            });
            return false;
        });
    });

function finishAjax(id, response){
  $('#loader').slideUp(300);
  $('#'+id).html(unescape(response));
  $('#'+id).fadeIn(200);

} 

Answer 1

Create variable a marker array. And then when create a marker, adding marker arrays. You can try to this one.

var markerArrays = new Array();
for (var i = 0; i < beaches.length; i++) {
    var beach = beaches[i];
    var myLatLng = new google.maps.LatLng(beach[1], beach[2]);
    // var polylines = new google.maps.LatLng(beach[1], beach[2]);
    polylines.push(new google.maps.LatLng(beach[1], beach[2]));

    var marker = createMarker(myLatLng,"This place",beach[0]);
    markerArrays.push(marker);
}

$.each(markerArrays, function(index, val) {
    val.setMap(null);
});