function getDirectory(doc){

   var lastSlash = doc.path.lastIndexOf("\\");
   var temp = doc.path.substr(0, lastSlash).split("\\");

   // format directory path url encoded
   for (var i=1; i<temp.length; i++) temp[i] = escape(temp[i]);
   return "file:///" + temp.join("/") + "/";
}

function saveTextToFile(text2save, fileName){

   var fileURI = getDirectory(flash.getDocumentDOM()) + fileName;

   var myOutput = flash.outputPanel;

   // clear, trace, save, and hide output;
   myOutput.clear();
   myOutput.trace(text2save);
   myOutput.save(fileURI, false);
   myOutput.clear();

   myOutput.trace(fileURI + " saved")
}

// example, that saves a file in the document directory
saveTextToFile("this is a basic jsfl example", "example.txt");