Use the below code on the page head which you want to prevent to be landed using back button
<script type="text/javascript">
function preventBack() { window.history.forward(); }
setTimeout("preventBack()", 0);
window.onunload = function() { null };
</script>
<script language="JavaScript" type="text/javascript">
javascript: window.history.forward(1);
</script>
And a lot more can be found here
logout button code...[
^]
Regards..:laugh: