Ajax跨域请求

<script type="text/javascript">  
 var btn = document.getElementById("btn");
 var url = document.getElementById("url");
 var date = document.getElementById("date");
 var mohu = document.getElementById("flag");
    btn.onclick=function(){
    $.ajax({
        type : "get",
        async:false,
        url : "http://localhost:8080/ec-dec/page/pv.img?url="+url+"&date="+date+"&flag="+flag,
        dataType : "jsonp",
        jsonp: "callbackparam",//服务端用于接收callback调用的function名的参数
        jsonpCallback:"success_jsonpCallback",//callback的function名称
        success : function(json){
            alert(json);
            document.getElementById("showpvuv").innerHTML="<div align=‘center‘><h1><font size=‘10‘>PV:"+json[0].PV+"          UV:"+json[0].UV+"</font></h1></div>";
        },
        error:function(){
            alert(‘fail‘);
        }
    });};
</script>  

  public void getPVUV(HttpServletRequest request,HttpServletResponse response){
        
        String flag = request.getParameter("flag");
        
        String url = request.getParameter("url");
        
        String date = request.getParameter("date");
        
        long pv = this.qService.getPV(url, date, flag);
        
        long uv = this.qService.getUV(url, date, flag);
            
        String json= "([{PV:"+pv+", UV:"+uv+"}])";//组合成json字符串
        
          String callback=request.getParameter("callbackparam"); 
    
        try {
            response.getWriter().print(callback+json);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }