Send to back/front of other selected object by script?

Perhaps you could log the zOrderPosition of the targetObject, then move the desired object down in the list until it's zOrderPosition is less than the target's zOrder Position? Something like below.. (this is untested).

var targetObject = doc.selection[0];

var objectToMove = doc.selection[1]; // i don't know if this will work to determine the correct source and target objects

var targetPosition = targetObject.zOrderPosition;

while (objectToMove.zOrderPosition > targetPosition)

{

     objectToMove.zOrder(ZOrderMethod.SENDBACKWARD)

}

Not at all Carlos. I am very sorry if I did not make myself clear. I really appreciate the help given by Silly-V and you.  I will learn with the answers and try to build this script or use your sugestions. Thank you

The answer you seek is in this command:

PageItem move (relativeObject: Object, insertionLocation: ElementPlacement)

Here is the necessary ElementPlacement  enumeration:

INSIDE

PLACEATBEGINNING

PLACEATEND

PLACEBEFORE

PLACEAFTER

Some example code :

var doc = app.activeDocument;
var myItem = doc.pathItems[0];
myItem.move(doc.layers[1], ElementPlacement.INSIDE); // places item into another layer (if it starts in a different layer, obviously)
//myItem.move(doc.layers[1], ElementPlacement.PLACEAFTER); // throws error "Cannot move to specified location"

myItem = doc.pathItems.getByName('test');
myItem.move(doc.groupItems.getByName('my group'), ElementPlacement.PLACEBEFORE); // moves it above a group named 'my group' in the stacking order
myItem.move(doc.groupItems.getByName('my group'), ElementPlacement.PLACEAFTER); // moves it below a group named 'my group' in the stacking order
myItem.move(doc.groupItems.getByName('my group'), ElementPlacement.INSIDE); // moves it inside a group named 'my group', at the top of the stacking order
myItem.move(doc.groupItems.getByName('my group'), ElementPlacement.PLACEATBEGINNING); // moves it inside a group named 'my group', at the top of the stacking order just like ElementPlacement.INSIDE
myItem.move(doc.groupItems.getByName('my group'), ElementPlacement.PLACEATEND); // moves it inside a group named 'my group', at the bottom of the stacking order

Now let's see if it can even work with different documents!

  var doc = app.activeDocument;
  var myItem = doc.pathItems.getByName('test');

  var newDoc = app.documents.add();
  var newLayer = newDoc.layers.add();
  newLayer.name = "New Layer!";
  myItem.move(newLayer, ElementPlacement.INSIDE); // moves the item into a specified new layer in a new script-added document, although my AI crashed when doing this test for the 1st time. Not sure why, but it's good now.