document.oncontextmenu=rtret;
window.document.onkeydown = getcode;
//window.document.onkeydown=rtret;
window.document.onselectstart =rtret;
 function  getcode()
 {

        if(event.ctrlKey)
        {
         if((event.keyCode == 78) ||(event.keyCode == 110) ||(event.keyCode == 65) ||(event.keyCode == 67) || (event.keyCode ==97) || (event.keyCode == 99))
             {event.returnValue = false;
         return false;}
        }

         if((event.keyCode == 16) || (event.keyCode == 17) )
         {
          return false;
         }

 }
function rtret()
 {window.event.returnValue=false; }