When there is no selection, how can I obtain all paragraphs and table cells in the document?

If no objects are selected, all text Frames in current document will be processed.

I have two targets:
    1. Text paragraphs outside the table.
    2. Cells inside the table.
How can I get them?

Like this:

obj.texts[0].appliedParagraphStyle)=parStn;
obj.texts[0].tables.everyItem().cells.everyItem().texts[0].appliedParagraphStyle = bodyParStn;

This is my code above.
It seems that it can only go up to this point: alert(“here”);
There is no response below that.

    var myDocument = app.documents.item(0);
    var myStory = myDocument.stories;
    for (var s = 0; s < myStory.length; s++) {
        alert("here");
      var what = "^.";
        var res = getGrepSearch(what, app.activeDocument);
        for (var f = 0; f <res.length; f++) {
            var obj = app.selection[f];
...
}
}