Browser disable refresh button

window.history.forward(1);
document.attachEvent("onkeydown", my_onkeydown_handler);
function my_onkeydown_handler()
{
switch (event.keyCode)
{
case 116 : // 'F5' event.returnValue = false; event.keyCode = 0; window.status = "We have disabled F5"; break;
}
}