When a field accepts multiple values, the admin form adds a button "Add another item". Mousedown submits a POST to /system/ajax to get another field (i'm using multifield here).

I'd like to hook into the javascript completed event to do some custom handling on those additional fields.

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How can I most easily hook these ajax calls for javascript callback and reference to the block being added? Is it possible without PHP?

  • 1
    Not sure if Drupal raises an event, but if not you could always use $( document ).ajaxComplete(function( event, xhr, settings ) { .. }
    – Clive
    Mar 9, 2016 at 0:29
  • @Clive, is there a better way to ID the original button clicked? I'm basically parsing the response for a string i'm familiar with in this block. Then doing a bunch more to check for attributes i'll manage as HTML is added and removed:
    – E.A.T
    Mar 9, 2016 at 6:54
  • $(document).ajaxComplete(function(event,xhr,settings){ if (settings.url.indexOf("/system/ajax") > -1) { var data = xhr.responseText; if (data) { data = JSON.parse(data); if (data.length > 0 && typeof data[1].data != 'undefined') { data = data[1].data; if (data.indexOf('field-search-radius') > -1) { console.log('i found you!'); } } } } });
    – E.A.T
    Mar 9, 2016 at 6:54
  • Client-side only? I don't think there is - you'd need to hook into the form ajax in PHP
    – Clive
    Mar 9, 2016 at 8:48

1 Answer 1


You can use hook_menu_alter and define your own custom callback function like below.

function demo_pane_menu_alter(&$items) {
  $items['system/ajax']['page callback'] = 'demo_pane_taxonomy_autocomplete';
  • Won't this break all Ajax operations?
    – Kevin
    Mar 9, 2016 at 5:02

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