My script works as an action but not as a script

Hi here is the code, it works as an action then when I convert it to script then it just does nothing, this is to go to end of working area in timeline in photoshop

#target photoshop

//

// Set.jsx

//

//

// Generated Thu Aug 23 2018 18:57:29 GMT+0200

//

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

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

//

//==================== Set ==============

//

function Set() {

  // Set

  function step1(enabled, withDialog) {

    if (enabled != undefined && !enabled)

      return;

    var dialogMode = (withDialog ? DialogModes.ALL : DialogModes.NO);

    var desc1 = new ActionDescriptor();

    var ref1 = new ActionReference();

    ref1.putProperty(cTID('Prpr'), cTID('time'));

    ref1.putClass(sTID("timeline"));

    desc1.putReference(cTID('null'), ref1);

    var desc2 = new ActionDescriptor();

    desc2.putInteger(sTID("seconds"), 4);

    desc2.putInteger(sTID("frame"), 29);

    desc2.putDouble(sTID("frameRate"), 30);

    desc1.putObject(cTID('T   '), sTID("timecode"), desc2);

    executeAction(cTID('setd'), desc1, dialogMode);

  };

  step1();      // Set

};

//=========================================

//                    Set.main

//=========================================

//

Set.main = function () {

  Set();

};

Set.main();

// EOF

"Set.jsx"

// EOF