Is Point within Polygon

gistfile1.js

GeoHelper.IsInPolygon=function(points,latlong)
{
    // This code adapted from the following URL:
    // http://msdn.microsoft.com/en-us/library/cc451895.aspx
    var i;
    var j=points.length-1;
    var inPoly=false;
    var lat = latlong.Latitude;
    var lon = latlong.Longitude;
    for (i=0; i<points.length; i++) 
    {
        if (points[i].Longitude<lon && points[j].Longitude>=lon ||  points[j].Longitude<lon && points[i].Longitude>=lon) 
        {
            if (points[i].Latitude+(lon-points[i].Longitude)/(points[j].Longitude-points[i].Longitude)*(points[j].Latitude-points[i].Latitude)<lat) 
            {
                inPoly=!inPoly; 
            }
        }
        j=i; 
    }
    return inPoly; 
};