function select()
{
	if (window.getSelection) { return window.getSelection().getRangeAt(0); } 
	else if (window.document.selection) { return window.document.selection.createRange(); }
	return false;	
}

var obj, w = window;
  if (window.attachEvent) { obj = function (element, event, handler) { element.attachEvent('on' + event, handler); } }
  else 
  {
     obj = function (element, event, handler) { element.addEventListener(event, handler, false); };
  }
	
function res () 
{  	
	if(rang = select())
	{	
                // не добавляется обработчик события
		obj(rang.startContainer, 'keydown',  function(e) { alert(23423) } );	
	}
}

obj(w, 'mousedown', res);