as2.0 里很简单
var myparam = network;

as3.0 就稍微复杂一点
var paramObj:Object= root.loaderInfo.parameters;
var myparam = paramObj['bg'];
trace(myparam);

用JavaScript实现：
<script language="JScript">
<!-
var LocString=String(window.document.location.href);
function GetQueryString(str){
var rs=new RegExp("(^|)"+str+"=([^\&]*)(\&|$)","gi").exec(LocString),tmp;
...