Array contains latitude and longitude of a polygon in Google maps drawingManager

Question 1

Create a global array which will contains your polygons

var polygons = [];

Then, fill your array in polygoncomplete event :

google.maps.event.addDomListener(drawingManager, 'polygoncomplete', function(polygon) {
    polygons.push(polygon);

In order to let the users the possibility to edit polgons after creation, you have to call setEditable at the end of your polygonComplete event

polygon.setEditable(true);

if you need to read all the lat/lng of polygon's vertices, you can use this sample of code :

var polygonBounds = polygon.getPath();
var coordinates = [];

for(var i = 0 ; i < polygonBounds.length ; i++)
{
    coordinates.push(polygonBounds.getAt(i).lat(), polygonBounds.getAt(i).lng());
}

Question 2

Just copy and then use.

<html>

<!--Here you will create a polygon by tools that Google maps "drawingManager" gives to you and then you have an array named "coordinates" as an output. This array saves all latLng of the polygon. When you edit the polygon it also edit this variable too.
!-->

<head>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=true&libraries=drawing"></script>

<!--Global variables!-->
<script>
//This variable gets all coordinates of polygone and save them. Finally you should use this array because it contains all latitude and longitude coordinates of polygon.
var coordinates = [];

//This variable saves polygon.
var polygons = [];
</script>

<script>
//This function save latitude and longitude to the polygons[] variable after we call it.
function save_coordinates_to_array(polygon)
{
    //Save polygon to 'polygons[]' array to get its coordinate.
    polygons.push(polygon);

    //This variable gets all bounds of polygon.
    var polygonBounds = polygon.getPath();

    for(var i = 0 ; i < polygonBounds.length ; i++)
    {
        coordinates.push(polygonBounds.getAt(i).lat(), polygonBounds.getAt(i).lng());
        alert(i);
    }   
}
</script>

<script>
function initialize()
{
    //Create a Google maps.
    var map = new google.maps.Map(document.getElementById('map'), {zoom: 12, center: new google.maps.LatLng(32.344, 51.048)});

    //Create a drawing manager panel that lets you select polygon, polyline, circle, rectangle or etc and then draw it.
    var drawingManager = new google.maps.drawing.DrawingManager();
    drawingManager.setMap(map);

    //This event fires when creation of polygon is completed by user.
    google.maps.event.addDomListener(drawingManager, 'polygoncomplete', function(polygon) {
        //This line make it possible to edit polygon you have drawed.
        polygon.setEditable(true);

        //Call function to pass polygon as parameter to save its coordinated to an array.
        save_coordinates_to_array(polygon);

        //This event is inside 'polygoncomplete' and fires when you edit the polygon by moving one of its anchors.
        google.maps.event.addListener(polygon.getPath(), 'set_at', function () {
            alert('changed');
            save_coordinates_to_array(polygon);
            });

        //This event is inside 'polygoncomplete' too and fires when you edit the polygon by moving on one of its anchors.
        google.maps.event.addListener(polygon.getPath(), 'insert_at', function () {
            alert('also changed');
            save_coordinates_to_array(polygon);
            });
    });
}

google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>

<body>
<div style="width:1024px; height:768px;" id="map"></div>
</body>

</html>