FramerMaker doesn't export chapter number in bookmarks in Acrobat

Here is an Acrobat JavaScript. I will post a video link explaining how it works and how to use it.

if (app.viewerVersion >= 10) {

    // Add a toolbutton for the command.
    app.addToolButton ({cName: "NumberBookmarksCmd",
        cTooltext: "Number Bookmarks",
        cExec: "numberBookmarks();",
        cEnable: "event.rc = (event.target != null);",
        nPos: 0 });

} 
else { // 9 or below.
  
    // Add the Convert Bookmarks to Title Case menu item to the Document menu.
    app.addMenuItem ({cName: "NumberBookmarksCmd",
        cUser:"Number Bookmarks",
        cParent: "Document",
        cExec: "numberBookmarks();",
        cEnable: "event.rc = (event.target != null);" });
}

// Make a global counter variable to count the bookmarks
// that should be numbered.
counter = 0;

function numberBookmarks () {
	
	processBookmarks (this.bookmarkRoot);
}

function processBookmarks (bkm) {

    var numberRegex = /^Body \- (.+)$/,
        otherRegex = /^[^-]+ \- (.+)$/;
    
    if (numberRegex.test (bkm.name) === true) {
        counter += 1;
        bkm.name = bkm.name.replace (numberRegex, "Ch " + counter + " $1");
    }
    else {
        bkm.name = bkm.name.replace (otherRegex, "$1");
    }

    if (bkm.children != null) {
        for (var i = 0; i < bkm.children.length; i++) {
            processBookmarks (bkm.children[i]); 
        } 
    }
}