var isnn,isie
if(navigator.appName=='Microsoft Internet Explorer') //check the browser
{  isie=true }

if(navigator.appName=='Netscape')
{  isnn=true }

function right(e) //to trap right click button
{
        if (isnn && (e.which == 3 || e.which == 2 ))
                return false;
        else if (isie && (event.button == 2 || event.button == 3))
        {
                alert("Sorry, you do not have permission to right click on this page.");
                return false;
        }
                return true;
}

function key(k)
{
        if(isie) {
                if(event.keyCode==17 || event.keyCode==18 || event.keyCode==93) {
                        alert("Sorry, you do not have permission to press this key.")
                        return false;
                 }
        }

        if(isnn){
                alert("Sorry, you do not have permission to press this key.")
                return false; }
}

if (document.layers) window.captureEvents(Event.KEYPRESS);
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (document.layers) window.captureEvents(Event.MOUSEUP);
document.onkeydown=key;
document.onmousedown=right;
document.onmouseup=right;
window.document.layers=right;