Add ErrorHandler to share behavior

radicale/web/internal_data/index.html

@@ -200,6 +200,7 @@
       <form>
         <button type="button" class="green" data-name="cancel">Close</button>
       </form>
+      <span class="error hidden" data-name="error"></span>
     </section>
 
     <section id="newshare" class="container hidden">
@@ -233,6 +234,7 @@
         <button type="submit" class="green" data-name="submit">Create</button>
         <button type="button" class="red" data-name="cancel">Cancel</button>
       </form>
+      <span class="error hidden" data-name="error"></span>
     </section>
 
     <section id="createcollectionscene" class="container hidden">
@@ -312,4 +314,4 @@
   </main>
 </body>
 
-</html>
+</html>