[nikita.mmf]

var handler = function ( event ){
  event = event || window.event;
  var target = event.target || event.srcElement;
  if ( target.nodeType == 1 && target.nodeName.toLowerCase == "input" && target.type == "checkbox" && target.checked ) {
    var inputs = document.getElementsByTagName("input");
    for ( var i = 0; inputs[i]; i++ ) {
      if ( inputs[i].type="checkbox" && inputs != target ) {
        inputs[i].checked = false;
      }
    }
  }
}
if (document.body.addEventListener){
  document.body.addEventListener('click', handler, false); 
} else if (document.body.attachEvent){
  document.body.attachEvent('onclick', handler);
}