wfs例子上的有关问题_GIS

wfs例子上的问题
在 http://openlayers.org/dev/examples/wfs-states.html （官网例子）中可用看到橙黄色的美国States图层覆盖在上面，我把openlayers官网里的 wfs美国领土states例子下到自己的电脑上，当然是html和js文件都下了，但是在自己的机子上却只能看见底图（http://labs.metacarta.com/wms-c/Basic.py 的basic图层）。

下面是两段源码：
wfs-states.js代码:
var map;
OpenLayers.ProxyHost = "proxy.cgi?url=";

function init() {
map = new OpenLayers.Map("map");

var base = new OpenLayers.Layer.WMS("OpenLayers WMS",
"http://labs.metacarta.com/wms-c/Basic.py",
{layers: "basic"}
);
map.addLayer(base);

var wfs = new OpenLayers.Layer.Vector("States", {
strategies: [new OpenLayers.Strategy.BBOX()],
protocol: new OpenLayers.Protocol.WFS({
url: "http://demo.opengeo.org/geoserver/wfs",
featureType: "states",
featureNS: "http://www.openplans.org/topp"
})
});
map.addLayer(wfs);

map.zoomToExtent(new OpenLayers.Bounds(-140.4, 25.1, -44.4, 50.5));
}

wfs-states.html代码：
<html>
<head>
<link rel="stylesheet" href="../theme/default/style.css" type="text/css" />
<link rel="stylesheet" href="style.css" type="text/css" />
<title>WFS: United States (GeoServer)</title>
<script src="../OpenLayers.js"></script>
<script src="wfs-states.js"></script>
</head>

<body onload="init()">
<h1 id="title">WFS United States (GeoServer) Example</h1>
<div id="tags"></div>
<p id="shortdesc">
Shows the use of the WFS United States (GeoServer).
</p>
<div id="map" class="smallmap"></div>
<div id="docs">
<p>

This example shows the basic use of a vector layer with the
WFS protocol.
</p>
<p>
See the <a href="wfs-states.js" target="_blank">wfs-states.js
source</a> to see how this is done.
</p>
</div>
</body>
</html>

文件放置的目录应该是没错的……大家有遇见这种情况的吗？
本地显示[/align]

------解决方案--------------------
javascript有cross domain security限制，你没有配置跨域访问，就无法通过js代码用wfs查询的方式访问远程服务器的地图属性信息。