I have a div with custom attribute `posx`

```
<div class="js__scroll__canvas" posx="0">

```

Another js plugin set dynamic value to posx on scroll.

I try to catch `posx` is change.

```
$(".js__scroll__canvas").attr( "posx" ).change(function() {
    alert( "Handler for .change() called." );
}); 

```

Nothing alerts. How to catch it? Help please