implement client-side verification of Change note

src/slc/quickchangenote/browser/javascript.pt

@@ -1,6 +1,33 @@
 <tal:script replace="structure string:<script" /> type="text/javascript"<tal:script replace="structure string:>" />
-    var notes = <tal:notes replace="view/json_notes" />;
     jQuery(function($){
-        $("#cmfeditions_version_comment").autocomplete(notes);
+        var notes = <tal:notes replace="view/json_notes" />;
+        var commentfield = $("#cmfeditions_version_comment");
+
+        /* Mark as required */
+        var span = document.createElement("span");
+        $(span).css("color", "red").attr("title", "Required").addClass(
+            "required").append(document.createTextNode(" " + "\u25a0"));
+        commentfield.parent().find("label").append(span);
+
+        /* Set up autocomplete */
+        commentfield.autocomplete(notes);
+
+        /* Clear any error formatting on change note once it is filled in */
+        commentfield.change(function(){
+            commentfield.parent().toggleClass('error', false);
+        });
+
+        /* Check that the change note field has been entered */
+        var form = commentfield.closest("form");
+        form.submit(function(){
+            if(commentfield.val().length == 0){
+                commentfield.parent().toggleClass("error", true);
+                /* Remove this class from the submit button, otherwise we
+                 * might be prompted to confirm a resubmit */
+                $(":submit", form).toggleClass("submitting", false);
+                return false;
+            }
+            return true;
+        });
     });
 <tal:script replace="structure string:</script>" />