Google Maps - maintain current position and zoom when reloading dynamic map pointers - php

Question

I have been searching high and low for a solution to this problem. I fetch dynamic positions of markers and show the map positioned and zoomed baased on the City that has been selected in my application. If I then scroll or zooom the Google map and then request an update of the markers position (by fetching the xml) I loose the new position and zoom I was at. How do I make the function check what the current getCenter and getZoom is to use in the reload of the map ?
function load() {
if(map) { // Does not work
var lat = map.getCenter().lat();
var lng = map.getCenter().lng();
var zoom = map.getZoom();
} else {
var lat = '<?=$Lat?>';
var lng = '<?=$Lon?>';
var zoom = <?=$zoom?>;
}
var map_options = {
center: new google.maps.LatLng(lat,lng),
zoom: zoom,
mapTypeId: '<?=$map_type?>'
};
var map = new google.maps.Map(document.getElementById("map"), map_options);
var infoWindow = new google.maps.InfoWindow;
<< Other marker creating code here that works fine >>
}

Answer 1

remove the var? to make the lat,lng, zoom global var
if(map) { // Does not work
lat = map.getCenter().lat();
lng = map.getCenter().lng();
zoom = map.getZoom();
} else {
lat = '<?=$Lat?>';
lng = '<?=$Lon?>';
zoom = <?=$zoom?>;
}
UPDATE
move the var map outside of function load() {}
something like this:
var map, lat, lng, zoom;
function load(){...map = new google.maps.Map(document.getElementById("map"), map_options);
...}
let me explain this shortly
when page is loaded var map is initiated as "nothing/null", therefore if(map) will be false then
use the lat,lng,zoom from your PHP
after map = new
google.maps.Map(document.getElementById("map"),
map_options); , map holders the js
object of gmap.
then load(){...} is called again if(map) is true then the
block will be executed