给你个例子。
后台Java代码：

     @RequestMapping(value = "/friendLinks/friendLinksList.do")
    public void getfriendLinksList(HttpServletRequest request,
            HttpServletResponse response, ModelMap modelMap){

        response.setCharacterEncoding("UTF-8");
        String pageNoStr = request.getParameter("pageNo");
        Integer pageNo = 0;

        try {
            pageNo = Integer.valueOf(pageNoStr);
        } catch (Exception e) {
            pageNo = 0;
        }
        Page page = new Page();
        page.setPageNo(pageNo);

        //按分页条件查询用户
        List<FriendLinks> linksList = null;
        try {
            linksList = friendLinksService.getFriendLinksList(page);
            //将查出来的友情链接和分页信息放到json字符串中
            JSONArray jsonList = new JSONArray();
            JSONObject bj = JSONObject.fromObject(page);
            jsonList.add(bj);
            for (FriendLinks links : linksList) {
                JSONObject obj = JSONObject.fromObject(links);
                jsonList.add(obj);
            }
            response.getWriter().println(jsonList.toString());
            response.getWriter().flush();
            response.getWriter().close();
        } catch (Exception e) {

            e.printStackTrace();
        }
        return ;
    }

JS中代码：

     function fillData(pageNo) {
    if (pageNo == "") {
        pageNo = thisPageNo;
    }

    var stateValue = $("#stateValue").val();
    var titleValue = $("#titleValue").val();

    $.ajax({
            url:contextPath + "/friendLinks/friendLinksList.do", 
            type:"POST",
            data:{
                  pageNo:pageNo,
                  stateValue:stateValue,
                  titleValue:titleValue
                 }, 
            dataType:"json", 
            beforeSend:function () {
            $("#pageTd a").remove();
    }, success:function (data) {
            var page = data[0];
            if (page.count == 0) {
                var noDataMsg = "<tr><td colspan=\"9\" class=\"xiamian\">无相关数据</td></tr>";
                $("#dataBody").html(noDataMsg);
                var pageMsg = "总记录数：<strong>0</strong>"+
                              "&nbsp;&nbsp;当前页：<strong>0/0</strong>&nbsp;&nbsp;"+
                              "<a href='javascript:;'>首页</a>&nbsp;"+
                              "<a href='javascript:;'>上一页</a>&nbsp;"+
                              "<a href='javascript:;'>下一页</a>&nbsp;"+
                              "<a href='javascript:;'>尾页</a>&nbsp;";
                              $("#pageButtonBefore").html(pageMsg);
            } else {
                var dataMsg = "";
                var caozuo = "";
                var useOrNot = "";
                for (var i = 1; i < data.length; i++) {
                    caozuo = "";
                    caozuo = caozuo + "<a href='javascript:;' onclick='checkJump(\""+data[i].id+"\")'>查看</a>";
                    caozuo = caozuo + "<a href='javascript:;' onclick='editJump(\""+data[i].id+"\")'>修改</a>";
                    caozuo = caozuo + "<a href='javascript:;' onclick='deleteJump(\""+data[i].id+"\")'>删除</a>";


                    if(data[i].status == "0"){

                        status = "是";
                    }else{
                        status = "否";
                    }
                    dataMsg = dataMsg + "<tr><td>" + i + 
                                        "</td><td>" + data[i].linkName + 
                                        "</td><td>" + data[i].linkSite + 
                                        "</td><td>" + status + "</td><td>"; 
                    dataMsg = dataMsg + caozuo;                 
                    dataMsg = dataMsg + "</td></tr>";
                }
                $("#dataBody").html(dataMsg);

                var pageMsg = "总记录数：<strong>"+page.count+"</strong>&nbsp;&nbsp;当前页：<strong>"+page.pageNo+"/"+page.totalPage+"</strong>&nbsp;&nbsp;"+
                              "<a href='javascript:fillData(\"1\");'>首页</a>&nbsp;&nbsp;"+
                              "<a href=javascript:fillData(\"" + page.pre + "\");>上一页</a>&nbsp;&nbsp;"+
                              "<a href=javascript:fillData(\"" + page.next + "\");>下一页</a>&nbsp;&nbsp;"+
                              "<a href=javascript:fillData(\"" + page.totalPage + "\");>尾页</a>&nbsp;&nbsp;";
                $("#pageButtonBefore").html(pageMsg);
            }
    }, error:function () {
          alert("获取相关数据失败！");
    }});
    }

其实能看出来，JS怎么接收值跟后台用什么方式传没有多大关系，关键是看传过来的值格式是啥就好了。
传回来的是字符串，那就直接按照字符串处理，传回来的是Json格式的那就直接按照解析Json来处理。

一般都是用get方法获得

js一般通过ajax发送http请求，获取后台返回数据。ajax主要使用XMLHttpRequest返回值通过在回调函数中使用函数responseText和responseXml。当然直接使用JQuery等js框架更方便

推荐你一本书《全端Web开发：使用JavaScript与Java》