How can i pass the `this` with other parameters to function? Tried the following without success:

```js
    function update_alt($this,my_param){
        this_alt=$(this).attr('alt');
        $(this).attr('alt',this_alt+my_param);
    }

//  $('.asd img').each(update_alt); // passing $this ok
    $('.asd img').each(update_alt(this,prompt('alt?',''))); // null

```