--- a/jslib/urweb.js	Tue Dec 30 11:33:31 2008 -0500
+++ b/jslib/urweb.js	Tue Dec 30 15:53:04 2008 -0500
@@ -1,11 +1,18 @@
-function sc(v) { return {v : v} }
+function callAll(ls) {
+  for (; ls; ls = ls.next)
+    ls.v();
+}
 
-function ss(s) { return {v : s.v} }
-function sr(v) { return {v : v} }
-function sb(x,y) { return {v : y(x.v).v} }
+function sc(v) { return {v : v, h : null} }
+function sv(s, v) { s.v = v; callAll(s.h); }
+
+function ss(s) { return s }
+function sr(v) { return {v : v, h : null} }
+function sb(x,y) { return {v : y(x.v).v, h : null} }
 
 function dyn(s) {
   var x = document.createElement("span");
   x.innerHTML = s.v;
   document.body.appendChild(x);
+  s.h = { n : s.h, v : function() { x.innerHTML = s.v } };
 }