I'm completely confused by "app.documents[0].selection"and "app.activeDocument.selection[0]"

[dublove]

When I select a text box, both of the following are correct:

var sel = app.documents[0].selection;
alert(sel); // [object TextFrame]
alert(sel.length) // 1​

When my cursor is inside the text, I tried the code below and found both are [object TextFrame], but sel.length is invalid..
It should be noted that sel is undefined.

    item = app.activeDocument.selection[0];
    if (item.parent.textFrames[0].constructor.name == "TextFrame") {
        var sel = item.parent.textFrames[0];
    }
    alert(sel);//[object TextFrame]
    alert(sel.length)//undefined?????

[m1b]

@dublove there's usually no difference between app.activeDocument and app.documents[0].

Your problem is simply that sometimes the line

var sel = item.parent.textFrames[0];

doesn't get called, due to the predicate, so it will throw an error.

If you want to handle the error gracefully, do it like this:

var item = app.activeDocument.selection[0];

// must define sel outside the if/else
var sel;

if (item.parent.textFrames[0].constructor.name == "TextFrame") {
    sel = item.parent.textFrames[0];
}
else {
    sel = { length: 0 };
}

alert(sel);
alert(sel.length);

[dublove]

Hi m1b.

As you mentioned, is the value of sel.length 0?
But sel is already an object [object TextFrame].
If that's the case, my sort(a,b) interaction below won't capture the objects and will throw an error.

Actually, I just want to automatically obtain the final TextFrame based on different selections.

 alert(item.constructor.name);
    var sel;
    item = app.activeDocument.selection[0];
    if (item.parent.textFrames[0].constructor.name == "TextFrame") {
        sel = item.parent.textFrames[0];
    }
    else if (
        item.constructor.name == "Image"
        || item.constructor.name == "TextFrame") {
        sel = app.documents[0].selection;
    }
        sel.sort(function (a, b) {
        var aBounds = a.visibleBounds;
        var bBounds = b.visibleBounds;
 
        if (aBounds[1] < bBounds[1]) {
            return -1;
        } else if (aBounds[1] > bBounds[1]) {
            return 1;
        }
        else {
            return bBounds[0] - aBounds[0];
        }
    });

[james_1465]

Really helpful breakdown — I’ve run into similar issues where features behave differently depending on device or context. It reminds me how important it is to double-check workflows across platforms, whether it’s Excel or even how a website displays on mobile vs desktop. Consistency really makes or breaks productivity.

[Laubender]

@m1b said: "there's usually no difference between app.activeDocument and app.documents[0]."

Hi @dublove ,

the difference between app.documents[0] and app.activeDocument is a subtle one.

It could be that the addressed document with app.documents[0] is a document without a layout window.

Not so with app.activeDocument. That is always one with a layout window.

Let's proof that; start InDesign with no document open and add two documents with a different parameter for showingWindow in method add():

// START InDesign WITH NO OPEN DOCUMENT:
// Add two documents:
var doc1 = app.documents.add(); // showingWindow parameter true is default
var doc2 = app.documents.add( false ); // showingWindow parameter set to false

alert( app.documents.length ) ; // returns 2

alert( app.activeDocument == doc1 ); // returns true

Regards,
Uwe Laubender
( Adobe Community Expert )

[dublove]

@Laubender 

Too deep.
Can't grasp it all at once.
How do I make `sel = item.parent.textFrames[0];` into a real, controllable object?

It should be controllable like `sel = app.documents[0].selection;`.

I tried using
alert(app.documents[0].selection.parent);
but app.documents[0].selection doesn't seem to support parent.

It seems like alert(app.documents[0].selection[0].parent.textFrames[0]);
But sel.app.documents[0].selection[0].parent.textFrames[0];
still cannot be recognized as a real textFrame.
It remains a fake (logical textFrame?)

[dublove]

Hi @m1b @Laubender 

In other words, the textFrame obtained through conversion is not a true selection object.
It is not a collection and does not have a length property.
Does it need to be converted into a collection?

sel = [item.parent.textFrames[0]];

This time sort(a,b) didn't trigger an alert.

But the subsequent alert(“A:” + sel[0].parentPage) is invalid.

@m1b Is it possible to have something similar to the image?
As long as the cursor is within the text box, always return the textFrame object.

    var doc = app.activeDocument,
        items = doc.selection;
var graphics = getGraphics(doc.selection);
function getGraphics(items) {
    var graphics = [];
    if ('Array' === items.constructor.name) {
        for (var i = 0; i < items.length; i++)
            graphics = graphics.concat(getGraphics(items[i]));
    }

    else if (
        items.hasOwnProperty('allGraphics')
        && items.allGraphics.length > 0
    )
        graphics = graphics.concat(items.allGraphics);
    else if (
        items.hasOwnProperty('allPageItems')
        && items.allPageItems.length > 0
    )
        graphics = graphics.concat(getGraphics(items.allGraphics));
    else if ('Image' === items.constructor.name) {
        graphics.push(items);
    }
    return graphics;
};

[m1b · Accepted solution]

@dublove yes definitely. That is the way I would code it. I had a quick search and I have already written a function (for you, back in 2022!). Here is an example usage:

/**
 * @author m1b
 */
function main() {

    var doc = app.activeDocument;
    var sel = getTextFrames(doc.selection);

    alert('sel = ' + sel + ' (length: ' + sel.length + ')');

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Test');

/**
 * Returns any text frames found in given `items`.
 * @author m1b
 * @version 2025-09-05
 * @param {DOM item} items - a DOM item or items to search in, eg. doc.selection.
 * @returns {Array<TextFrame>}
 */
function getTextFrames(items) {

    if (undefined == items)
        return [];

    var parentTextFrame;
    var found = [];

    if (!items.hasOwnProperty('0'))
        items = [items];

    for (var i = 0, item; i < items.length; i++) {

        item = items[i];

        if ('TextFrame' === item.constructor.name)
            found.push(item);

        else if (
            // item contains textFrames
            item.hasOwnProperty('textFrames')
            && item.textFrames.length > 0
        )
            found = found.concat(getTextFrames(item.textFrames));


        else if (
            // is contained by textFrame(s)
            item.hasOwnProperty('parentTextFrames')
            && item.parentTextFrames.length > 0
        )
            found = found.concat(getTextFrames(item.parentTextFrames));


        else if (
            // is in a story, which may contain textFrames
            item.hasOwnProperty('parentStory')
        )
            found = found.concat(getTextFrames([item.parentStory]));


        // has a parent which might be a textFrame
        else if (item.hasOwnProperty('parent')) {

            var parent = item.parent;

            while (
                'Document' !== parent.constructor.name
                && !parentTextFrame
            ) {
                parentTextFrame = item.parent;

                if ('TextFrame' === parent.constructor.name) {
                    parentTextFrame = item.parent;

                }

            }

        }

        if (
            parentTextFrame
            && 'TextFrame' === parentTextFrame.constructor.name
        )
            // store the parent text frame
            found.push(parentTextFrame);

        else if (
            // contains page items, which may be textFrames
            item.hasOwnProperty('pageItems')
            && item.pageItems.length > 0
        )
            found = found.concat(getTextFrames(item.pageItems));

    }

    return found;

};

Edit 2025-09-05: fixed bug in getTextFrames function that caused stack overrun.

[dublove]

Hi m1b.

You're incredibly formidable, far ahead of your time.
Back in 2022, I didn't even have the capacity to recognize this issue existed.

This is perfect. The problem is solved in an instant.

Thank you very much.

[dublove]

Hi @m1b 

Is there a table version?
Whether you select text within a cell, select a cell, or select a table, it always returns "Table".
When the cursor is inside a table, I don't want to get textFrame.

[m1b · Accepted solution]

@dublove I wrote this function for getting the table. Not sure how good it is.

- Mark

function main() {

    var doc = app.activeDocument;
    var table = getTable(doc.selection);

    alert(table);

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Test');

/**
 * Attempts to return a Table, given an object.
 * @author m1b
 * @version 2023-02-06
 * @param {InsertionPoint|Text|Cells|Table|TextFrame} obj - an object related to a Cell.
 * @returns {Cell}
 */
function getTable(obj) {

    if (obj == undefined)
        return;

    if ('Array' === obj.constructor.name) {
        for (var i = 0, table; i < obj.length; i++) {
            table = getTable(obj[i]);
            if (table && table.isValid)
                return table;
        }
        return;
    }

    if (obj.constructor.name == 'Cell')
        return obj.parent;

    if (obj.parent.constructor.name == 'Cell')
        return obj.parent.parent;

    if (
        obj.hasOwnProperty('cells')
        && obj.cells.length > 0
    )
        return obj.cells[0].parent;

    if (
        obj.hasOwnProperty('tables')
        && 0 !== obj.tables.length
    )
        return obj.tables[0];

};

[dublove]

@m1b 

There's an issue:

If I currently have an image selected,

getTextFrames(doc.selection) does not return null.    Instead, it incorrectly displays my entire script code.

getGraphics(doc.selection) does not seem to have this issue. Even if I select text, it returns null(Nothing unusual occurred.).

In other words, if getTextFrames() fails to retrieve results, it will throw an error.

var doc = app.activeDocument;
var items = doc.selection;
var grs = getGraphics(doc.selection);
var tfs = getTextFrames(doc.selection);

[m1b]

Thanks @dublove, I have corrected the bug in my getTextFrames function.

- Mark

[dublove]

Hi m1b.

Thank you very much.

This morning I used `graphics.length > 0 for the check.
Now ,haver replaced TextFrames, no exceptions.

Can TextFrames be divided into two scenarios:
A: Cursor inside the table.
B: Cursor outside the table.

Because sometimes when the cursor is inside the table, I don't want the text box to be affected.
Alternatively, it can be distinguished like this:

if(getTextFrames && !table) {
}

[dublove]

Hi @m1b 

If a text box is selected, it contains two tables.
getTable(doc.selection); only returns one table.

Is it possible to restrict the return to all tables within the text box, or all tables in the Story?

Additionally, when the cursor is within a cell, `getTable(doc.selection)` is not a collection and does not have a length property.

[dublove]

Hi @m1b 

Found a minor bug:
When  cells are selected, 'getTextFrames' does not retrieve the textFrame.