batch change project items size, like:null, comp, etc.

change project item size.jsx

app.beginUndoGroup("resize null");
var s = app.project.activeItem.selectedLayers;
var o = Number(prompt("new size", 100));
for (var i = 0; i < s.length; i++) {
 try {
  s[i].source.width = s[i].source.height = o;
 } catch (e) {}
}
app.endUndoGroup();