问Ajax函数调用第二次不起作用

EN

 My code is:     VIEW PAGE =>

 $(document).ready(function() {  
 $("body").on('change','#assettype_id',function(e){  // "assettype_id" is 
                                                       dropdown id
  //e.preventDefault();   
   var categoryval = $('#assettype_id :selected').val();                         
   $.ajax({   
              type: 'POST',  
              cache: false,  
              url: 'http://my_path/index.php/assetcontroller/assignpc/'+ categoryval,  // Based on "categoryval" data will change in div tag  
              dataType: 'html',  
              success: function(data) {  
              $( "#result" ).load( "http://my_path/index.php/assetcontroller/assignpc/"+ categoryval);  // "result" is div tag id  
              $( "#result" ).html(categoryval);   
 },  
});  
    return false;  
  });  
 });