Please refer the below steps.
1. First create a page SessionClear.aspx and write the code to clear session
2. Then add following JavaScript code in your page or Master Page:-
<script language="javascript" type="text/javascript">
var isClose = false;
//this code will handle the F5 or Ctrl+F5 key
//need to handle more cases like ctrl+R whose codes are not listed here
document.onkeydown = checkKeycode
function checkKeycode(e) {
var keycode;
if (window.event)
keycode = window.event.keyCode;
else if (e)
keycode = e.which;
if(keycode == 116)
{
isClose = true;
}
}
function somefunction()
{
isClose = true;
}
//<![CDATA[