Exact : the same questions generally lead to the same answers !
http://groups.google.com/group/google-maps-js-api-v3/search?hl=en_US&...
/**
* @desc Check if polygon contains point.
* @return boolean
**/
GPolygon.prototype.Contains = function(point) {
var j=0;
var oddNodes = false;
var x = point.lng();
var y = point.lat();
for (var i=0; i < this.getVertexCount(); i++) {
j++;
if (j == this.getVertexCount()) {j = 0;}
if (((this.getVertex(i).lat() < y) && (this.getVertex(j).lat()
>= y))
|| ((this.getVertex(j).lat() < y) && (this.getVertex(i).lat() >=
y))) {
if ( this.getVertex(i).lng() + (y - this.getVertex(i).lat())
/ (this.getVertex(j).lat()-this.getVertex(i).lat())
* (this.getVertex(j).lng() - this.getVertex(i).lng())<x ) {
oddNodes = !oddNodes;
}
}
}
return oddNodes;
};