force browser to reload page on back button pressed. CREDIT: http://stackoverflow.com/questions/20899274/how-to-refresh-page-on-back-button-click

reloadonbackbutton.js

<input type="hidden" id="refreshed" value="no">
<script type="text/javascript">
onload=function(){
var e=document.getElementById("refreshed");
if(e.value=="no")e.value="yes";
else{e.value="no";location.reload();}
}