if (document.attachEvent) {
    document.attachEvent("onkeydown", __DisableKeydown);
}
else {
    document.addEventListener("keydown", __DisableKeydown, false);
}

function __DisableKeydown(ev) {

    if (ev == null) ev = window.event;
    var keyCode = ev.keyCode ? ev.keyCode : ev.charCode;

    // Only Works in IE (beafun ap)
    if (window.navigator.appName != "Microsoft Internet Explorer") return;

    // Disable function keys except for F11.
    if (keyCode >= 112 && keyCode <= 123 && keyCode != 122) {
        event.keyCode = 0;
        return false;
    } 

    // Disable Ctrl hot keys except for Ctrl + Shift/Space/A/X/C/V.
    if (window.event.ctrlKey && keyCode != 17 && (keyCode != 16 && keyCode != 32 && keyCode != 88 && keyCode != 67 && keyCode != 86 && keyCode != 65)) {

        event.keyCode = 0;
        return false;
    }

    // Disable the Esc key.
    if (keyCode == 27) {
        event.keyCode = 0;
        return false;
    }

    // Disable the menu key.
    if (keyCode == 93) {
        event.keyCode = 0;
        return false;
    }

    // Disable the backspace key
    if (keyCode == 8) {
        var TagName = event.srcElement.tagName.toUpperCase();
        if (!(TagName == "INPUT" || TagName == "TEXTAREA")) {
            event.keyCode = 0;
            return false;
        }
    }

}

// no context menu
document.oncontextmenu = new Function("return false");
document.ondragstart = new Function("return false");