function clickIE() {
    if (document.all) {
        return false;
    }
}
function clickNS(e) {
    if (document.layers||(document.getElementById&&!document.all)) {
        if (e.which==2||e.which==3) {
            return false;
        }
    }
}
if (document.layers) {
        document.captureEvents(Event.MOUSEDOWN);document.onmousedown=clickNS;
} else {
        document.onmouseup=clickNS;document.oncontextmenu=clickIE;
}