added a loading image in class select histogram

Author: Gaurav SinghaRoy

app/assets/images/ajax-loader.gif

@@ -166,6 +166,7 @@ QueryBuilder = {
         },
         add_class_details : function(element,class_uri,tab_level){
             element.attr('class-uri',class_uri);
+            element.find('strong').first().after("<span class='loading-image'>&nbsp;&nbsp;&nbsp;<img  height=\"10px\" src=\"/assets/horizontal-loading.gif\"></span>");
             $.getJSON(QueryBuilder.classes.get_examples_action_url(class_uri),function(data){
                 var element_append_html = "&nbsp;&nbsp;&nbsp;<span class='badge'>"+data.total_objects.toString()+"</span>";
                 if(data.total_objects > 0){
@@ -177,6 +178,7 @@ QueryBuilder = {
                     }
                     element_append_html += "&nbsp;)</small>";   
                 }
+                element.find(".loading-image").first().remove();
                 element.find("strong").after(element_append_html);
             });
             QueryBuilder.classes.add_subclasses_details(element,class_uri,tab_level);