I wanted to execute JavaScript in a Java program. Rhino looked like it would do the trick, but there is no DOM without a browser, and i wanted to run browser-less. I found a lot of discussion around this but none worked just right. Here is the incantation i used:

document = new Object ();
document.writeln = function (s)
{
  if (s instanceof Array)
           for (x in s)
               document.writeln (s[x]);
  else
           java.lang.System.out.println (s);
}
document.write = function (s)
{
   if (s instanceof Array)
       for (x in s)
                document.write (s[x]);
   else
       java.lang.System.out.print (s);
}

I imagine i could extend it to capture most of what a browser's DOM contains; maybe some day.
I also modified RunScript to read from System.in and inject the above code:

import java.io.FileReader;
import org.mozilla.javascript.*;

public class RunScript
{
public static void main(String args[]) throws
java.io.FileNotFoundException, java.io.IOException
{
String s = "document = new Object ();" +
   "document.writeln = function (s)" +
       "{ java.lang.System.out.println (s); };" +
   "document.write = function (s)" +
       "{ java.lang.System.out.print (s); };";

   Context cx = Context.enter();
   try {
       Scriptable scope = cx.initStandardObjects();

       Object result = cx.evaluateString (scope, s, "<prelude>", 1, null);

       FileReader in = new FileReader (args[0]);

       result = cx.evaluateReader (scope, in, args[0], 1, null);

       System.err.println(Context.toString(result));

   }
   finally
   {
       Context.exit();
   }
}
}