function dropdown(lnk)
{
     var nav = document.getElementById('dlink'+lnk);
     var tab = document.getElementById('dmenu'+lnk);

     var onfunc=function()
     {      
      tab.style.display='block';
     };
     var offfunc=function()
     {     
      tab.style.display='none';
     };

     addEvent(nav,'mouseover',onfunc);
     addEvent(tab,'mouseover',onfunc);

     addEvent(nav,'mouseout',offfunc);
     addEvent(tab,'mouseout',offfunc);

}

function addEvent( obj, type, fn ) {
  if ( obj.attachEvent ) {
    obj['e'+type+fn] = fn;
    obj[type+fn] = function(){obj['e'+type+fn]( window.event );}
    obj.attachEvent( 'on'+type, obj[type+fn] );
  } else
    obj.addEventListener( type, fn, false );
}