fixes #1504

app/assets/javascripts/notes.js

@@ -360,7 +360,11 @@ Danbooru.Note = {
       var $note_box = Danbooru.Note.Box.find(id);
       var text = $textarea.val();
       $note_body.data("original-body", text);
-      Danbooru.Note.Body.set_text($note_body, text);
+      Danbooru.Note.Body.set_text($note_body, "Loading...");
+      $.get("/note_previews.json", {body: text}).success(function(data) {
+        Danbooru.Note.Body.set_text($note_body, data.body);
+        $note_body.show();
+      });
       $this.dialog("close");
 
       if (id.match(/\d/)) {
@@ -386,8 +390,11 @@ Danbooru.Note = {
       var id = $this.data("id");
       var $note_body = Danbooru.Note.Body.find(id);
       var text = $textarea.val();
-      Danbooru.Note.Body.set_text($note_body, text);
+      Danbooru.Note.Body.set_text($note_body, "Loading...");
-      $note_body.show();
+      $.get("/note_previews.json", {body: text}).success(function(data) {
+        Danbooru.Note.Body.set_text($note_body, data.body);
+        $note_body.show();
+      });
     },
 
     cancel: function() {

app/controllers/note_previews_controller.rb

@@ -0,0 +1,12 @@
+class NotePreviewsController < ApplicationController
+  respond_to :json
+
+  def show
+    @body = DText.sanitize(params[:body].to_s)
+    respond_with(@body) do |format|
+      format.json do
+        render :json => {:body => @body}.to_json
+      end
+    end
+  end
+end

config/routes.rb

@@ -120,6 +120,7 @@ Danbooru::Application.routes.draw do
     end
   end
   resources :note_versions, :only => [:index]
+  resource :note_previews, :only => [:show]
   resources :pools do
     member do
       put :revert