diff --git a/module/task/js/start.ui.js b/module/task/js/start.ui.js
new file mode 100644
index 0000000000..090ea917bb
--- /dev/null
+++ b/module/task/js/start.ui.js
@@ -0,0 +1,20 @@
+/* If left = 0, warning. */
+$('button[type="submit"]').on('click', function()
+{
+    var left     = parseFloat($("#left").val());
+    var consumed = parseFloat($("#consumed").val());
+    if(!left)
+    {
+        var result;
+        if(!consumed)
+        {
+            alert(noticeTaskStart);
+            result = false;
+        }
+        else
+        {
+            result = confirm(confirmFinish);
+        }
+        if(!result) return false;
+    }
+})
diff --git a/module/task/ui/start.html.php b/module/task/ui/start.html.php
index 09f83d8380..3697dab32f 100644
--- a/module/task/ui/start.html.php
+++ b/module/task/ui/start.html.php
@@ -10,6 +10,8 @@ declare(strict_types=1);
  */
 namespace zin;
 /* ====== Preparing and processing page data ====== */
+jsVar('confirmFinish', $lang->task->confirmFinish);
+jsVar('noticeTaskStart', $lang->task->noticeTaskStart);
 
 /* zin: Set variables to define control for form. */
 if($task->mode == 'linear')