JavaScript中获得URL请求参数

<mce:script type="text/javascript"><!--
function URL(url) {
url = url || "http://blog.csdn.net/xxd851116";
this.url = url.toString() ;
}

URL.prototype.getValue = function(key) {
if (this.url == null) return;
if (key == null) return;
var key_values = this.url.split("?")[1].split("&");
for (var i = 0; i < key_values.length ; i++ )
{
var key_value = key_values[i].split("=");
if (key == key_value[0])
{
return key_value[1];
}
}
}

var url = "http://www.google.cn/search?hl=zh-CN&newwindow=1&q=%E7%AC%91%E7%9A%84%E8%87%AA%E7%84%B6&meta=&aq=f&oq=" ;
var url = new URL(url);
document.writeln("hl = " + url.getValue("hl") + ";<br/>");
document.writeln("q = " + url.getValue("q") + ";<br/>");
// --></mce:script>