diff --git a/lib/zin/wg/gantt/js/v1.js b/lib/zin/wg/gantt/js/v1.js
index 78506fe0a8..f9251e6e1a 100644
--- a/lib/zin/wg/gantt/js/v1.js
+++ b/lib/zin/wg/gantt/js/v1.js
@@ -21,3 +21,17 @@ function getRemoteScript(url, successCallback, errorCallback)
     script.src = url;
     document.head.appendChild(script);
 }
+
+/**
+ * Update export progress.
+ *
+ * @param  int $progress
+ * @access public
+ * @return void
+ */
+function updateProgress(progress)
+{
+    let progressText = ganttLang.exporting;
+    if(progress < 1) progressText += Math.floor(progress * 100) + '%';
+    $('#mainContent').attr('data-loading', progressText);
+}