diff --git a/js/gl.js b/js/gl.js
index cf2a972f..5697bf89 100644
--- a/js/gl.js
+++ b/js/gl.js
@@ -615,7 +615,7 @@ var importObject = {
             return Math.floor(Math.random() * 2147483647);
         },
         now: function () {
-            return Date.now() / 1000.0;
+            return performance.now() / 1000.0;
         },
         canvas_width: function () {
             return Math.floor(canvas.width);