ctrl tuşunu iptal etme / js

< script type = "text/javascript" >
  var isNS = (navigator.appName == "Netscape") ? 1 : 0;

if (navigator.appName == "Netscape") document.captureEvents(Event.MOUSEDOWN || Event.MOUSEUP);

function mischandler() {
  return false;
}

function mousehandler(e) {
  var myevent = (isNS) ? e : event;
  var eventbutton = (isNS) ? myevent.which : myevent.button;
  if ((eventbutton == 2) || (eventbutton == 3)) return false;
}
document.oncontextmenu = mischandler;
document.onmousedown = mousehandler;
document.onmouseup = mousehandler;
var isCtrl = false;
document.onkeyup = function(e) {
  if (e.which == 17)
    isCtrl = false;
}

document.onkeydown = function(e) {
  if (e.which == 17)
    isCtrl = true;
  if (((e.which == 85) || (e.which == 117) || (e.which == 65) || (e.which == 97) || (e.which == 67) || (e.which == 99)) && isCtrl == true) {
    // alert(‘Keyboard shortcuts are cool!’);
    return false;
  }
}