Find the first character of a footnote on a page

Hi @effi2003, I have written a script along the lines of your script above, but I didn't use its code because it was strange and very incomplete. Perhaps this will give you an idea of some approaches to your problem. I've made it somewhat configurable via the `settings` object in the code.

There are quick instructions in the code, but let me know if you don't understand anything or if it has bugs. 🙂

- Mark

P.S. I have added my demo.indd file which you can try the script out with, if you want to first match my result below.

/**
 * @file Decorate Footnotes.js
 *
 * Usage:
 * 
 *   0. First configure the `settings` object below to suit your needs.
 * 
 *   1. Select a page item. This is the decoration item that will be anchored
 *      to each footnote. Note: in Mode.CURRENT_STORY, you must select the
 *      decoration item AND a text frame containing the target story. The script
 *      will know which is which.
 * 
 *   2. Run Script, which will anchor a copy of the decoration into footnotes
 *      as per the settings configuration.
 *
 * @author m1b
 * @version 2025-01-30
 * @discussion https://community.adobe.com/t5/indesign-discussions/find-the-first-character-of-a-footnote-on-a-page/m-p/15120332
 */
function main() {

    var DecorationPosition = {
        BEFORE_FOOTNOTE_REFERENCE: 0,
        AFTER_FOOTNOTE_REFERENCE: 1,
        AFTER_DELIMITER: 2,
    };

    var Mode = {
        CURRENT_STORY: 'Current Story Only',
        ALL_STORIES: 'All Document Stories',
        CURRENT_PAGE: 'Current Page Only',
    };

    // CONFIGURE SCRIPT HERE:
    var settings = {

        // the object style to use for positioning of the decoration item
        anchoredObjectStyleName: 'Footnote Decoration',

        // which insertion point to use, can be a `DecorationPosition`
        // or a number where 0 is first insertion point (before footnote reference)
        insertionIndex: DecorationPosition.AFTER_DELIMITER,

        // the operational mode: can be Mode.CURRENT_STORY, Mode.ALL_STORIES, Mode.CURRENT_PAGE
        mode: Mode.CURRENT_STORY,

        // whether to remove existing anchored items first
        removeExistingDecorations: true,

        // whether to show alert dialog after script runs
        showResults: true,

    };

    var doc = app.activeDocument,
        items = doc.selection;

    if (
        Mode.CURRENT_STORY === settings.mode
        && 2 !== items.length
    )
        return alert('Please select a page item to use as decoration AND a text frame containing the target story and try again.');

    else if (
        Mode.CURRENT_STORY !== settings.mode
        && 1 !== items.length
    )
        return alert('Please select a single page item to use as decoration and try again.');

    var footnotes = [],
        item = items[0];

    if (
        Mode.ALL_STORIES === settings.mode
        || Mode.CURRENT_PAGE === settings.mode
    )
        footnotes = app.activeDocument.stories.everyItem().footnotes.everyItem().getElements();

    else if (Mode.CURRENT_STORY === settings.mode) {

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

            if (
                items[i].hasOwnProperty('footnotes')
                && items[i].footnotes.length > 0
            )
                // footnotes from the target story
                footnotes = items[i].parentStory.footnotes.everyItem().getElements();
            else
                // the decoration item
                item = items[i];

        }
    }

    if (0 === footnotes.length)
        return alert('No footnotes found.');

    var anchoredObjectStyle = doc.objectStyles.itemByName(settings.anchoredObjectStyleName);

    if (!anchoredObjectStyle.isValid)
        return alert('Could not find "' + settings.anchoredObjectStyleName + '" object style.');

    var counter = 0;

    for (var i = footnotes.length - 1; i >= 0; i--) {

        if (!footnotes[i].isValid)
            continue;

        if (settings.removeExistingDecorations) {
            // remove existing anchored objects from first paragraph
            var existing = footnotes[i].paragraphs[0].pageItems;
            for (var j = existing.length - 1; j >= 0; j--)
                existing[j].remove();
        }

        // target insertion point
        var ip = footnotes[i].paragraphs[0].insertionPoints[settings.insertionIndex].getElements()[0];

        if (
            Mode.CURRENT_PAGE === settings.mode
            && doc.layoutWindows[0].activePage !== ip.parentTextFrames[0].parentPage
        )
            continue;

        // anchor the new decoration
        anchorItems([item.duplicate()], ip, anchoredObjectStyle);
        ip.parentStory.recompose();
        counter++;

    }

    if (settings.showResults)
        alert('Decorate Footnotes\nMode: ' + settings.mode + '\nDecorations added: ' + counter);

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

/**
 * Anchors supplied `items`, one at a time,
 * to the supplied `insertionPoint`. Can apply
 * an optional Object Style to each item.
 * Note the insertionPoint will move along
 * so that each anchored item will be added
 * after the previous one.
 * @author m1b
 * @version 2024-01-05
 * @param {Array<PageItem>} items - indesign page items.
 * @param {InsertionPoint} insertionPoint - the place to add the items.
 * @param {ObjectStyle} [anchoredObjectStyle] - the object style to apply to each item (default: none).
 */
function anchorItems(items, insertionPoint, anchoredObjectStyle) {

    if (undefined == items)
        throw error('anchorSelectedPageItems failed: no `items` supplied.');

    if (undefined == insertionPoint)
        throw error('anchorSelectedPageItems failed: no `insertionPoint` supplied.');

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

        // do the insertion
        items[i].anchoredObjectSettings.insertAnchoredObject(insertionPoint);

        if (
            undefined != anchoredObjectStyle
            && anchoredObjectStyle.isValid
            && undefined != items[i].clearObjectStyleOverrides
        ) {
            // apply style
            items[i].appliedObjectStyle = anchoredObjectStyle;
            // clear overrides
            items[i].clearObjectStyleOverrides();
        }

    }

};

Edit 2025-01-30: to add demo.indd and screenshot.