On cleanup remove also id and data- attributes.

app/assets/javascripts/app/lib/app_post/utils.coffee

@@ -205,13 +205,16 @@ class App.Utils
       .removeAttr('title')
       .removeAttr('lang')
       .removeAttr('type')
+      .removeAttr('id')
+      .removeAttrs(/data-/)
     html
       .removeAttr('style')
       .removeAttr('class')
       .removeAttr('title')
       .removeAttr('lang')
       .removeAttr('type')
-
+      .removeAttr('id')
+      .removeAttrs(/data-/)
     html
 
   @_removeComments: (html) ->

app/assets/javascripts/application.js

@@ -174,13 +174,27 @@ jQuery.event.special.remove = {
 // native checkbox focus behaviour is the following:
 // tab to checkbox: :focus state and focus outline
 // click on checkbox: :focus state but no focus outline
-$('body').on('click', '.checkbox-replacement, .radio-replacement', function(event){ 
+$('body').on('click', '.checkbox-replacement, .radio-replacement', function(event){
   $(event.currentTarget).find('input').addClass('is-active')
 });
-$('body').on('blur', '.checkbox-replacement input, .radio-replacement input', function(){ 
+$('body').on('blur', '.checkbox-replacement input, .radio-replacement input', function(){
   $(this).removeClass('is-active')
 });
 
+// remove attributes by regex
+// http://stackoverflow.com/questions/8968767/remove-multiple-html5-data-attributes-with-jquery
+jQuery.fn.removeAttrs = function(regex) {
+  return this.each(function() {
+    var $this = $(this),
+      names = [];
+    $.each(this.attributes, function(i, attr) {
+      if (attr && attr.specified && regex.test(attr.name)) {
+        $this.removeAttr(attr.name);
+      }
+    });
+  });
+};
+
 // start application
 jQuery(function(){
   new App.Run();

public/assets/tests/html_utils.js

@@ -432,6 +432,11 @@ test("htmlCleanup", function() {
   result = App.Utils.htmlCleanup($(source))
   equal(result.html(), should, source)
 
+  source = "<div><p id=\"123\" data-id=\"abc\">some link to somewhere</p></div>"
+  should = "<p>some link to somewhere</p>"
+  result = App.Utils.htmlCleanup($(source))
+  equal(result.html(), should, source)
+
   source = "<div><small>some link to somewhere</small></a>"
   //should = "<div>some link to somewhere</div>"
   should = "some link to somewhere"