New to drupal 7, following code should work fine according to my knowledge can someone help me why ajax give me error in console ? and what the solution


function user_activity_tree_structure_showoptional_form($form, &$form_state, $base_nid) {
      $form['enablecond'] = array(
        '#type' => 'checkbox',
        '#title' => "Checkbox  ",
        '#ajax' => array(
        'callback' => 'ajaxcall_func',
        'progress' => 'false',
    return $form;

function ajaxcall_func(&$form, $form_state) 
    return null;

Console Error

js_Y5H_CdmZpIvEir8-B6htnqHb6_vJBznC3jPygHLV6dE.js:495 Uncaught TypeError: Cannot read property 'Drupal' of undefined
at Object.attach (js_Y5H_CdmZpIvEir8-B6htnqHb6_vJBznC3jPygHLV6dE.js:495)
at Object.<anonymous> (js_UYCsqqVg9hDgzN1bjf7T6Fy66IJRk810uQF1qy9Lgo4.js:61)
at Function.each (js_H_BqcoIBkzDSvN9rxK_RAvqVRCfKG3dcLloVRen-E84.js:4)
at Object.Drupal.attachBehaviors (js_UYCsqqVg9hDgzN1bjf7T6Fy66IJRk810uQF1qy9Lgo4.js:59)
at Drupal.ajax.success (js_Y5H_CdmZpIvEir8-B6htnqHb6_vJBznC3jPygHLV6dE.js:2127)
at Object.success (js_Y5H_CdmZpIvEir8-B6htnqHb6_vJBznC3jPygHLV6dE.js:1858)
at Object.c.success (js_Y5H_CdmZpIvEir8-B6htnqHb6_vJBznC3jPygHLV6dE.js:111)
at c (js_H_BqcoIBkzDSvN9rxK_RAvqVRCfKG3dcLloVRen-E84.js:4)
at Object.fireWith [as resolveWith] (js_H_BqcoIBkzDSvN9rxK_RAvqVRCfKG3dcLloVRen-E84.js:4)
at k (js_H_BqcoIBkzDSvN9rxK_RAvqVRCfKG3dcLloVRen-E84.js:6)

1 Answer 1


There was actually a conflict between Drupal 7 - contributed module -> navbar -> js -> displace.js with fancytree.js.

Just answering this question so that you should make sure that any third party library shouldn't conflict with core and contributed modules js libraries.

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