javascript - Set and change Jcrop image with an ajax query -

i want use jcrop on image obtained , changes ajax query. don't find way script work. @ moment script looks this:

 <script>     $(function () {          function jcrop_show_coords(c) {              $('#roi_x1').val((c.x).tofixed(1));             $('#roi_y1').val((c.y).tofixed(1));             $('#roi_x2').val((c.x2).tofixed(1));             $('#roi_y2').val((c.y2).tofixed(1));         };          var jcrop_api; // holder api         $('#img_ref').jcrop({             truesize: [100, 100],              setselect:   [1.0, 1.0, 99.0, 99.0],             onchange: jcrop_show_coords,               onselect: jcrop_show_coords         },function(){             jcrop_api = this;         });          function get_img() {             $.ajax({                                                       url: '/ajax/get_img.php',                 type: "post",                 data: {  idref: $("#idref").val() },                 datatype: 'json',                 success: function(resp) {                     jcrop_api.setimage(resp.img);                 }             });         };          $("#submit_data").on('click', function(){              get_img();         });     }); </script> 

and firebug says jcrop_api undefined in line:

jcrop_api.setimage(resp.img); 

any ideas how make work?

in html

 <img src="#" id="img_ref"/> 

in js

   function get_img() {         $.ajax({                                                   url: '/ajax/get_img.php',             type: "post",             data: {  idref: $("#idref").val() },             datatype: 'json',             success: function(resp) {                 $("#img_ref").attr("src",resp.imgpath);                 $('#img_ref').jcrop({                     truesize: [100, 100],                      setselect:   [1.0, 1.0, 99.0, 99.0],                     onchange: jcrop_show_coords,                       onselect: jcrop_show_coords                });             }         });     };      $("#submit_data").on('click', function(){          get_img();     });