该方法大小写敏感
<script>
function fnOnload() {
document.getElementById("SystemTree").src = "TreeList.aspx?PID=" + GetQueryString("PID");
}
function GetQueryString(name) {
var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
var r = window.location.search.substr(1).match(reg);
if (r != null) return unescape(r[2]); return null;
}
</script>
</head>
<body onload="fnOnload()">