var myDocument = app.activeDocument;  
var myString = new String; 
 
var myFldrName = myDocument.filePath; 
var myTextName = myDocument.name.split(".indd").join("export.txt"); 
var myFile = File(myFldrName + "/" + myTextName); 
myFile.open("w"); 
myFile.write(myString); 
myFile.close(); 

app.doScript( myScriptFile, ScriptLanguage.javascript, myString);