var ua = navigator.userAgent.toLowerCase();

function handleclick(e) {
  if (ua.indexOf("msie")>0) {
    if (event.button >= 2) {
		document.oncontextmenu=new Function("return false");
		return false;
	}
  } else if (ua.indexOf("gecko")>=0) {
    if (e.button >= 2)
		document.oncontextmenu=new Function("return false");
		return false;
  }
}

function handleerror() { return true; }
window.onmousedown=handleclick;
document.onmousedown=handleclick;
window.onerror=handleerror;
document.onerror=handleerror;