Display of all strings values in $attribute

Here is a 2-minute video that illustrates a basic scripting solution:

https://youtu.be/jXNOxYYZWhE

Here is the code I am using in the video:

main ();

function main () {
    
    var doc, element;
    
    doc = app.ActiveDoc;
    // Make sure there is an active document.
    if (doc.ObjectValid () === 1) {
        element = doc.MainFlowInDoc.HighestLevelElement;
        // Make sure the document is structured.
        if (element.ObjectValid () === 1) {
            processElement (doc);
        }
    }
}

function processElement (doc) {
    
    var element, values;
    
    // Get the currently selected element.
    element = doc.ElementSelection.beg.child;
    if (element.ObjectValid () === 1) {
        // Call a function to get a comma-separated list of
        // Tails attribute values.
        values = getAttributeValues (element, "Tails");
        if (values) {
            // Apply the list to the "display" attribute
            // used in the Prefix rule.
            setAttributeValue (element, "Tails_display", values);
        }
    }    
}

function getAttributeValues (element, name) {
    
    var attrList = element.Attributes, i = 0;
    
    var attrList, count, i;
    
    attrList = element.Attributes;
    count = attrList.length;
    
    for (i = 0; i < count; i += 1) {
        if (attrList[i].name === name) {
            if (attrList[i].values.length > 0) {
        		return (Array.prototype.join.call (attrList[i].values, ", "));
            }
        }
    }
}

function setAttributeValue (element, name, value) {
    
    // Sets the value of an attribute on the element.
    
    var attrList = element.Attributes, i = 0;
    for (i = 0; i < attrList.length; i += 1) {
        if (attrList[i].name === name) {
            attrList[i].values[0] = value;
            element.Attributes  = attrList;
            return;
        }
    }
}