顺序#id传递给jQuery

I have various form with sequential id, and I'm trying to code a ajax function which could analyze id and call the proper PHP function. But obviously jQuery is having a problem about getting the right id.

I think code will explain better:

js file:

jQuery(document).ready(function($) {
    var num= /\d/

    $('#delete'+num).on( 'submit', function(e) {
        e.preventDefault();  // evito di far ricaricare la pagina dopo aver effettuato il submit

        $.post(
            my_vars.ajaxurl,
            {
                action : 'delete_bird',         
                id : form.find('input[name=id]').val(),
                user_id : form.find('input[name=user_id]').val(),
                table : form.find('input[name=table]').val()
            },
            function( response ) {
                 // qualcosa da eseguire se la richiesta è andata a buon fine
            }
         );            
    });             
});

The form created in a php file:

<form method='post' id='delete".$results[$j][0]."'>
        <input type='hidden' name='id' value=".$results[$j][0]." />
        <input type='hidden' name='user_id' value=".$results[$j][1]." />
        <input type='hidden' name='table' value=".$table_RapaciTelefono." />
        <input type='submit' value='Cancella' />
</form>

I hope I've been clear.

jQuery(document).ready(function($){

$('[id^="delete"').on( 'submit', function(e){
    e.preventDefault();  // evito di far ricaricare la pagina dopo aver effettuato il submit
    var form = $(this);

    $.post(
     my_vars.ajaxurl,
     {
        action : 'delete_bird',         
        id : form.find('input[name=id]').val(),
        user_id : form.find('input[name=user_id]').val(),
        table : form.find('input[name=table]').val()
     },

     function( response ) {
            // qualcosa da eseguire se la richiesta è andata a buon fine
     }
  );            
 });             
});

</div>