Something like:

var RDF = new RDFFile(file);
try {
  var conts = RDF.getAllContainers();
  for (var i=0; i<conts.length; i++) {
    var list = conts[i].getSubNodes();
    for (i=0; i<list.length; i++) {
      var subject = list[i].getSubject();
      alert(list[i].getAttribute("http://robert.accettura.com/sdat#string");
    }
  }
} catch(ex) {
}