处理中文乱码(新，比较万能)（encodeURI）
$.ajax({
type:"GET",
url:encodeURI(encodeURI("AJAXXmlServer")),
data:encodeURI(encodeURI("username="+username)),
dataType:"xml" ,
success:callback
});

1，页面端在传地址的时候用两次 encodeURI(encodeURI("username="+username));
String name=request.getParameter("username");
2 服务器端：URLDecoder.decode(name,"UTF-8");

//encodeURI("username="+中) ==="username=%E4%B8%AD"
//encodeURI(encodeURI("username="+中)) ======"username=%25E4%25B8%25AD"