function noBackButton()
{
   window.history.forward()
} 
// Call the noBackButton function
noBackButton(); 
// When the page loads, just to be sure.
window.onload=noBackButton(); 
// On an event, check cache state
window.onpageshow=function(evt) { if(evt.persisted) noBackButton() } 
// On unload page, do nothing
window.onunload=function() { void(0) }