<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window id="findfile-window" 
        title="Тест"
        orient="vertical"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <script type="application/x-javascript">
    <![CDATA[
    var list_filename = "C:\\list.txt"; 

function read(file_name) {
    try {
        netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
    } catch (e) {
        alert("Permission to read file was denied.");
    }
    var file = Components.classes["@mozilla.org/file/local;1"]
        .createInstance(Components.interfaces.nsILocalFile);
    file.initWithPath( file_name );
    if ( file.exists() == false ) {
        alert("File does not exist");
    }
    var is = Components.classes["@mozilla.org/network/file-input-stream;1"]
        .createInstance( Components.interfaces.nsIFileInputStream );
    is.init( file,0x01, 00004, null);
    var sis = Components.classes["@mozilla.org/scriptableinputstream;1"]
        .createInstance( Components.interfaces.nsIScriptableInputStream );
    sis.init( is );
    var output = sis.read( sis.available() );
    alert(output);
   // return output;
}
read(list_filename);
]]>
  </script>
</window>