Prova questo codice.... che disabilita tutti gli elementi figli di un elemento padre.

codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function protect(anObject, protection) {
 if (anObject == null) {
  return true;
 } // if (anObject == null)
 var members = anObject.children.length;
 var i = 0;
 for (i=0;i<members;i++) {
  var curObject = anObject.children.item(i);
  if (curObject != null) {
   protect(curObject,protection);
	} // if (curObject != null)
 } // for (i=0;i<=members;i++)
 anObject.disabled = protection;
 return true;
} // function protect(anObject, protection)
//-->
</script>


</head>
<body>
<div id="id1">
 <input type="text" id="text1" value="45415455054090">

 <input type="text" id="text2" value="45415455054090">

 <input type="text" id="text3" value="45415455054090">

 <input type="text" id="text4" value="45415455054090">

 <input type="text" id="text5" value="45415455054090">

</div>
<input type="button" value="Protect" onclick="protect(document.getElementById('id1'),true)">
<input type="button" value="Unprotect" onclick="protect(document.getElementById('id1'),false)">


da qui c'è un form
<form id="myform" action="" method="post">
<div id="id2">
 <input type="text" id="text10" value="45415455054090">

 <input type="text" id="text20" value="45415455054090">

 <input type="text" id="text30" value="45415455054090">

 <input type="text" id="text40" value="45415455054090">

 <input type="text" id="text50" value="45415455054090">

</div>
</form>
i bottoni sono fuori dalla form

<input type="button" value="Protect" onclick="protect(document.getElementById('myform'),true)">
<input type="button" value="Unprotect" onclick="protect(document.getElementById('myform'),false)">
</body>
</html>