At the moment to make dynamic top offset calculator on multiple elements, one would write:
``` javascript
$('.my-affix').each(function () {
var $el = $(this);
$el.affix({
offset: {
top: function () { return $el.offset().top; }
}
});
})
```
This patch will allow to:
``` javascript
$('.my-affix').affix({
offset: {
top: function ($el) { return $el.offset().top; }
}
});
```