diff -r e8916518b38d -r 445d5f1d4177 javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/KOList.java
--- a/javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/KOList.java	Thu Apr 04 13:08:26 2013 +0200
+++ b/javaquery/api/src/main/java/org/apidesign/bck2brwsr/htmlpage/KOList.java	Mon Apr 08 12:36:12 2013 +0200
@@ -30,6 +30,7 @@
     private final String name;
     private final String[] deps;
     private Knockout model;
+    private Runnable onchange;
 
     public KOList(String name, String... deps) {
         this.name = name;
@@ -39,6 +40,14 @@
     public void assign(Knockout model) {
         this.model = model;
     }
+    
+    public KOList<T> onChange(Runnable r) {
+        if (this.onchange != null) {
+            throw new IllegalStateException();
+        }
+        this.onchange = r;
+        return this;
+    }
 
     @Override
     public boolean add(T e) {
@@ -133,12 +142,15 @@
 
     private void notifyChange() {
         Knockout m = model;
-        if (m == null) {
-            return;
+        if (m != null) {
+            m.valueHasMutated(name);
+            for (String dependant : deps) {
+                m.valueHasMutated(dependant);
+            }
         }
-        m.valueHasMutated(name);
-        for (String dependant : deps) {
-            m.valueHasMutated(dependant);
+        Runnable r = onchange;
+        if (r != null) {
+            r.run();
         }
     }