if (window.Event)
document.captureEvents(Event.MOUSEUP);
function nocontextmenu() {
    event.cancelBubble = true
    event.returnValue = false;
    return false;
}

function norightclick(e) {
    if (window.Event) {
    if (e.which == 2 || e.which == 3)
    return false;
    } 
else
    if (event.button == 2 || event.button == 3) { 
    event.cancelBubble = true
    event.returnValue = false;
    return false;
    }
}

document.oncontextmenu = nocontextmenu; 
document.onmousedown = norightclick;