Refresh DownloadUrl on google map v3 and remove old markers - google-maps

Question

Hi I had a script and a xml file with 10.000 markers in it. I use markercluster to display the markers, but in order to fill the mobile browsers requierement I must begin the map at a certain zoom level (not to display to many markers). So I want to dynamically load the markers when the user change the zoom or viewport.
Here is my script. I thing I can't get the lat and lng of the LatLngBounds of the current viewport :
var customIcons = {
chambrehote: {
icon: '/wp-content/themes/codium-extend/images/chambre.png',
shadow: '/wp-content/themes/codium-extend/images/icon-shadow.png'
}
};
function initialize() {
var cluster = [];
var map = new google.maps.Map(document.getElementById("map_canvas"), {
center: new google.maps.LatLng('45.7676067','4.8351733'),
scrollwheel: false,
zoom: 12,
mapTypeId: 'roadmap'
});
var mcOptions = {gridSize: 100, styles: [
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m1.png",
width: 90
},
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m2.png",
width: 90
},
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m3.png",
width: 90
}
]};
var infoWindow = new google.maps.InfoWindow;
var bounds = new google.maps.LatLngBounds();
var swPoint = bounds.getSouthWest();
var nePoint = bounds.getNorthEast();
var swLat = swPoint.lat();
var swLng = swPoint.lng();
var neLat = nePoint.lat();
var neLng = nePoint.lng();
downloadUrl("/wp-content/themes/codium-extend/search/search_chambres.php?&type=chambrehote&codgeo=<?php echo $CODGEO ; ?>&radius=200&lat1="+swLat+"&lng1="+swLng+"&lat2="+neLat+"&lng2="+neLng+"", function(data) {
var xml = data.responseXML;
var markers = xml.documentElement.getElementsByTagName("marker");
for (var i = 0; i < markers.length; i++) {
var name = markers[i].getAttribute("name");
var address = markers[i].getAttribute("ville");
var slug = markers[i].getAttribute("slug");
var stars = markers[i].getAttribute("stars");
var type = markers[i].getAttribute("type");
var point = new google.maps.LatLng(
parseFloat(markers[i].getAttribute("lat")),
parseFloat(markers[i].getAttribute("lng")));
var html = "<b>" + name + "</b> " + "<br/>" + "" + "><a href=" + "/chambre-d-hote/" + slug + "/>lien vers la fiche</a>";
var icon = customIcons[type] || {};
//var icon = customIcons[type] || {};
var marker = new google.maps.Marker({
map: map,
position: point,
icon: icon.icon,
shadow: icon.shadow
});
bindInfoWindow(marker, map, infoWindow, html);
//bounds.extend(point);
//map.fitBounds(bounds);
google.maps.event.addListener(marker, 'click', (function(marker, i) {
return function() { infowindow.setContent(markers[i].getAttribute("name"));
infowindow.open(map, marker);
}
})(marker, i));
cluster.push(marker);
}
var mc = new MarkerClusterer(map,cluster,mcOptions);
});
}
function bindInfoWindow(marker, map, infoWindow, html) {
google.maps.event.addListener(marker, 'click', function() {
infoWindow.setContent(html);
infoWindow.open(map, marker);
});
}
function downloadUrl(url, callback) {
var request = window.ActiveXObject ?
new ActiveXObject('Microsoft.XMLHTTP') :
new XMLHttpRequest;
request.onreadystatechange = function() {
if (request.readyState == 4) {
request.onreadystatechange = doNothing;
callback(request, request.status);
}
};
request.open('GET', url, true);
request.send(null);
}
function doNothing() {}
function changePosition() {
var position = document.getElementById('position').value;
adUnit.setPosition(google.maps.ControlPosition[position]);
}
First point :
I think I couldn't get the value of swLat, swLng... for passing them to downloadUrl
And second point I certainly miss a listener somewhere but don't know where !
Thanks for your inputs
---- EDIT ----
Right now I can load dynamically the data when the idle is changed, but (there is a but) now each change a new marker is add even if it's already on the map. Is there a way to clean all the markers when the idle change before loading the new ones?
var cluster = [];
var map = new google.maps.Map(document.getElementById("map"), {
zoom: 12,
center: new google.maps.LatLng('45.7676067','4.8351733'),
mapTypeId: google.maps.MapTypeId.ROADMAP
});
var mcOptions = {gridSize: 100, styles: [
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m1.png",
width: 90
},
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m2.png",
width: 90
},
{
textColor: 'black',
height: 80,
url: "/wp-content/themes/codium-extend/images/cluster-m3.png",
width: 90
}
]};
var infoWindow = new google.maps.InfoWindow;
google.maps.event.addListener(map, 'idle', function() {
var bounds = map.getBounds();
var swPoint = bounds.getSouthWest();
var nePoint = bounds.getNorthEast();
var swLat = swPoint.lat();
var swLng = swPoint.lng();
var neLat = nePoint.lat();
var neLng = nePoint.lng();
// alert(swLng);
downloadUrl("/wp-content/themes/codium-extend/search/search_chambres.php?lat=45.7676067&lng=4.8351733&type=chambrehote&codgeo=<?php echo $CODGEO ; ?>&radius=2000&lat1="+swLat+"&lng1="+swLng+"&lat2="+neLat+"&lng2="+neLng+"", function(data) {
var xml = data.responseXML;
var markers = xml.documentElement.getElementsByTagName("marker");
for (var i = 0; i < markers.length; i++) {
var name = markers[i].getAttribute("name");
var address = markers[i].getAttribute("ville");
var slug = markers[i].getAttribute("slug");
var stars = markers[i].getAttribute("stars");
var type = markers[i].getAttribute("type");
var point = new google.maps.LatLng(
parseFloat(markers[i].getAttribute("lat")),
parseFloat(markers[i].getAttribute("lng")));
var html = "<b>" + name + "</b> " + "<br/>" + "" + "><a href=" + "/chambre-d-hote/" + slug + "/>lien vers la fiche</a>";
var icon = customIcons[type] || {};
//var icon = customIcons[type] || {};
var marker = new google.maps.Marker({
map: map,
position: point,
icon: icon.icon,
shadow: icon.shadow
});
bindInfoWindow(marker, map, infoWindow, html);
//bounds.extend(point);
//map.fitBounds(bounds);
google.maps.event.addListener(marker, 'click', (function(marker, i) {
return function() {
infowindow.setContent(markers[i].getAttribute("name"));
infowindow.open(map, marker);
}
})(marker, i));
cluster.push(marker);
}
var mc = new MarkerClusterer(map,cluster,mcOptions);
});
});
function bindInfoWindow(marker, map, infoWindow, html) {
google.maps.event.addListener(marker, 'click', function() {
infoWindow.setContent(html);
infoWindow.open(map, marker);
});
}
function downloadUrl(url, callback) {
var request = window.ActiveXObject ?
new ActiveXObject('Microsoft.XMLHTTP') :
new XMLHttpRequest;
request.onreadystatechange = function() {
if (request.readyState == 4) {
request.onreadystatechange = doNothing;
callback(request, request.status);
}
};
request.open('GET', url, true);
request.send(null);
}
function doNothing() {}
function changeFormat() {
var format = document.getElementById('format').value;
adUnit.setFormat(google.maps.adsense.AdFormat[format]);
}
function changePosition() {
var position = document.getElementById('position').value;
adUnit.setPosition(google.maps.ControlPosition[position]);
}