ファイルを読み込む

function hello(){

  var file = Components.classes["@mozilla.org/file/local;1"]

    .createInstance(Components.interfaces.nsILocalFile);

  file.initWithPath("C:\\lan.log");
  var fis = Components.classes["@mozilla.org/network/file-input-stream;1"]

    .createInstance(Components.interfaces.nsIFileInputStream);

  fis.init(file, -1, -1, 0);
  var lis = fis.QueryInterface(Components.interfaces.nsILineInputStream);

  var line = {};

  var c = [];
  while(lis.readLine(line)) {

    c.push(line.value);

  }
  fis.close();

  alert(c.join("\n"));

}