diff --git a/collects/scribble/scribble-common.js b/collects/scribble/scribble-common.js
new file mode 100644
index 00000000..9adaff17
--- /dev/null
+++ b/collects/scribble/scribble-common.js
@@ -0,0 +1,41 @@
+// Common functionality for PLT documentation pages
+
+function GetCookie(key) {
+  if (document.cookie.length <= 0) return null;
+  var cookiestrs = document.cookie.split(/; */);
+  for (var i in cookiestrs) {
+    var cur = cookiestrs[i];
+    var eql = cur.indexOf('=');
+    if (eql >= 0 && cur.substring(0,eql) == key)
+      return unescape(cur.substring(eql+1));
+  }
+  return null;
+}
+
+function SetCookie(key, val) {
+  var d = new Date();
+  d.setTime(d.getTime()+(365*24*60*60*1000));
+  document.cookie =
+    key + "=" + escape(val) + "; expires="+ d.toGMTString() + "; path=/";
+}
+
+function GotoPLTRoot() {
+  var u = GetCookie("PLT_Root");
+  if (u == null) return true; // no cookie: use plain up link
+  location = u;
+  return false;
+}
+
+function SetPLTRoot() {
+  SetCookie("PLT_Root", location);
+}
+
+function DoSearchKey(event, field) {
+  var val = field.value;
+  if (event && event.keyCode == 13 && val.indexOf("...search...") < 0) {
+    var u = GetCookie("PLT_Root");
+    if (u == null) u = "../"; // default: go up
+    u = u.replace(/[^\/\\]*$/, "") + "plt-search.html";
+    location = u + "?q=" + escape(val);
+  }
+}