var myDocument = app.activeDocument;

var dialog = new Window("dialog", "枠線", [100, 100, 480, 245]);
dialog.okButton = dialog.add("button", [180, 100, 180+50, 100+25], "実行", { name: "ok" });
dialog.cancelButton = dialog.add("button", [260, 100, 260+50, 100+25], "閉じる", { name: "cancel" });
var width = 0.25;
dialog.widthlabel = dialog.add("statictext", [20, 10, 20+130, 10+25], "罫線の幅(pt)");
dialog.width = dialog.add("edittext", [160, 10, 160+35, 10+25], width.toString());

dialog.okButton.onClick = function() {
  var color = new CMYKColor();
  color.black = 100;
  borderBox(dialog.width.text, color);
  dialog.close();
}
dialog.cancelButton.onClick = function() {
  dialog.close();
}

dialog.show();

/**
 * 選択された1つ以上のオブジェクトを罫で囲む
 * @param {Nuber] width 罫線の幅(pt)
 * @param {CMYKColor} color 色
*/
function borderBox(width, color) {
  var backunit = myDocument.rulerUnits;
  myDocument.rulerUnits = myDocument.rulerUnits.Points;
  for (var i = 0; i < myDocument.selection.length; i++) {
    var obj = myDocument.selection[i];
    var unit =obj.geometricBounds;
    var box = myDocument.pathItems.rectangle(unit[1], unit[0], Math.abs(unit[2] -unit[0]), Math.abs(unit[3] - unit[1]));
    box.filled = false;
    box.stroked = true;
    box.strokeWidth = width;
    box.strokeColor = color;
  }
  myDocument.rulerUnits = backunit;
}