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;
}
document.oncontextmenu=new Function("return false");