Fix issue with blockIntervalBar method

nginx/public_html/index.js

@@ -161,6 +161,9 @@ onload = function() {
                 }
             },
             blockIntervalBar: function(seconds) {
+                if (seconds < 0) {
+                    return "";
+                }
                 let minutes = Math.floor(seconds / 60);
                 return "*".repeat(minutes);
             },