jsonp获取服务器的数据，有两种
一，跨域
二，不跨域
如果跨域
js的写法有两种
1，
<script type="text/javascript">

  $(function() {
  $.getJSON('http://localhost:8090/search?jsoncallback=?',function(json) {
                    alert(json);
                    var html = "";
                    for (var key in json.data) {
                        html = html + "<img src='http://localhost:8090/img/99999/o/" + json.data[key].filename + "'><br>";
                        html = html + "名称:" + json.data[key].filename + "<br>";
                        html = html + "category:" + json.data[key].category + "<br>";
                        html = html + "height:" + json.data[key].height + "<br>";
                        html = html + "width:" + json.data[key].width + "<br>";
                        html = html + "length:" + json.data[key].length + "<br>";
                        html = html + "<hr>";
                    }

                    $('#imageList').html(html);
                }
                );
    });

</script>
get的ur后面有jsoncallback=?
这时候，要在服务器端增加如下代码
hr.getParameter("jsoncallback") +"({jsonp数据的格式})"
例子
jQuery1510062266528242707175_1324369820794({"data":[{"category" : "all","height" : "194","_id" : "4ebce7b5523e7e91029f910a","keyword" : "","width" : "259","chunkSize" : "262144","length" : "9082","md5" : "534a94756fc98a6db0483ee702297a82","filename" : "img001_images_029.jpeg","contentType" : "null","uploadDate" : "Fri Nov 11 18:15:33 JST 2011","aliases" : "null"},{"category" : "all","_id" : "4ebce7b5523e7e91029f9108","length" : "10987","md5" : "7b85b894132f78b2b90cd3fef27317a6","filename" : "img001_images_028.jpeg","aliases" : "null"}]});
注意，是如下格式jQuery1510062266528242707175_1324369820794({xxxx}),要加个()的哦。

2，get的ur后面有jsoncallback=?的写法可以改为get的ur后面有jsoncallback=getdata
同时   function(json) 前要加上getdata=
具体如下
<script type="text/javascript">

  $(function() {
  $.getJSON('http://localhost:8090/search?jsoncallback=getdata',getdata=function(json) {
                    alert(json);
                    var html = "";
                    for (var key in json.data) {
                        html = html + "<img src='http://localhost:8090/img/99999/o/" + json.data[key].filename + "'><br>";
                        html = html + "名称:" + json.data[key].filename + "<br>";
                        html = html + "category:" + json.data[key].category + "<br>";
                        html = html + "height:" + json.data[key].height + "<br>";
                        html = html + "width:" + json.data[key].width + "<br>";
                        html = html + "length:" + json.data[key].length + "<br>";
                        html = html + "<hr>";
                    }

                    $('#imageList').html(html);
                }
                );
    });

</script>
这个时候，服务器端就不需要加上hr.getParameter("jsoncallback")了，直接返回json格式就行了。


具体参见
http://www.cnblogs.com/5201314/archive/2009/06/23/1509552.html
http://51mst.iteye.com/blog/1170798

二，如果是不跨域的，
不需要加上jsoncallback，直接如下就行了，同时服务器返回的格式，就是纯jsonp的格式。
<script type="text/javascript">
  $(function() {
  $.getJSON('http://localhost:8090/search',function(json) {
                    alert(1);
                    var html = "";
                    for (var key in json.data) {
                        html = html + "<img src='http://localhost:8090/img/99999/o/" + json.data[key].filename + "'><br>";
                        html = html + "名称:" + json.data[key].filename + "<br>";
                        html = html + "category:" + json.data[key].category + "<br>";
                        html = html + "height:" + json.data[key].height + "<br>";
                        html = html + "width:" + json.data[key].width + "<br>";
                        html = html + "length:" + json.data[key].length + "<br>";
                        html = html + "<hr>";
                    }

                    $('#imageList').html(html);
                }
                );
    });

</script>
服务器返回代码
{"data":[{"category" : "all","aliases" : "null"}]}