Probá con DOMSubtreeModified.
Código PHP:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento sin título</title>
<script type="text/javascript">
</script>
</head>
<body>
<div id="dock_item_dialog_73209096">contenido original</div>
<script type="text/javascript">
document.getElementById('dock_item_dialog_73209096').addEventListener("DOMSubtreeModified", handler, true);
function handler(){
alert("hola");
}
</script>
<div onclick="document.getElementById('dock_item_dialog_73209096').innerHTML='boo!';">cambiar</div>
</body>
</html>