diff --git a/sketches/site4/tasks.js b/sketches/site4/tasks.js
new file mode 100644
index 0000000..e445e80
--- /dev/null
+++ b/sketches/site4/tasks.js
@@ -0,0 +1,16 @@
+document.addEventListener("DOMContentLoaded", function () {
+
+  console.log("greetings from javascript", window.location);
+  var name = window.location.href,
+      p = name.lastIndexOf("/");
+  name = name.substring(p+1);
+  var base = name.substring(0, name.length-5);
+  if (!base.endsWith("_rvrs")) {
+    var rvrs = base + "_rvrs.html";
+    var a = document.createElement("a");
+    a.href = rvrs;
+    a.target= "recto";
+    a.innerHTML = "flipside";
+    document.body.appendChild(a);
+  }
+});