The Art of Minimalism shown at HN

    function byId(id) {
      return document.getElementById(id);
    }

    function vote(node) {
      var v = node.id.split(/_/);   // {'up', '123'}
      var item = v[1]; 

      // hide arrows
      byId('up_'   + item).style.visibility = 'hidden';
      byId('down_' + item).style.visibility = 'hidden';

      // ping server
      var ping = new Image();
      ping.src = node.href;

      return false; // cancel browser nav
    }