Hi
you can restrict the user to go back with Backspace key by using following javascript...
<script type="text/javascript" language="javascript">
function cancelBack()
{
if ((event.keyCode == 8 ||
(event.keyCode == 37 && event.altKey) ||
(event.keyCode == 39 && event.altKey))
&&
(event.srcElement.form == null || event.srcElement.isTextEdit == false)
)
{
event.cancelBubble = true;
event.returnValue = false;
}
if (window.event.keyCode == 13)
{
event.returnValue=false;
event.cancel = true;
}
}
</script>