Howto monitor/display javascript processing

From a speed standpoint the script will be faster if the playback option is set to accelerated.

You could either give the user an alert at the start of the script asking them to wait while the script runs or just let the screen not refresh as you were doing. Depending on the script you could also use the wait for redraw funtion when needed. That would let the script run faster and let the user see some progress.

If the script really takes a long time a dialog with a progress bar would give the user an idea of how far along the script has run.

You can use the function below from Xbytor to set the playback options with a script. I don't think there is a way to determine the current settings.

cTID = function(s) { return app.charIDToTypeID(s); };
sTID = function(s) { return app.stringIDToTypeID(s); };

Stdlib = function Stdlib() {};

Stdlib.setActionPlaybackOptions = function(opt, arg) {
  function _ftn() {
    var desc = new ActionDescriptor();
    var ref = new ActionReference();
    ref.putProperty(cTID("Prpr"), cTID("PbkO"));
    ref.putEnumerated(cTID("capp"), cTID("Ordn"), cTID("Trgt"));
    desc.putReference(cTID("null"), ref );
    var pdesc = new ActionDescriptor();
    pdesc.putEnumerated(sTID("performance"), sTID("performance"), sTID(opt));
    if (opt == "pause" && arg != undefined) {
      pdesc.putInteger(sTID("pause"), parseInt(arg));
    }
    desc.putObject(cTID("T "), cTID("PbkO"), pdesc );
    executeAction(cTID("setd"), desc, DialogModes.NO);
  }
  _ftn();
};
Stdlib.setPlaybackAcclerated = function() {
  Stdlib.setActionPlaybackOptions("accelerated");
};
Stdlib.setPlaybackStepByStep = function() {
  Stdlib.setActionPlaybackOptions("stepByStep");
};
Stdlib.setPlaybackPaused = function(delaySec) {
  Stdlib.setActionPlaybackOptions("pause", delaySec);
};