Answers.Body: <p>My first thought is (similar to what Pete's suggesting) to try:
  <a href="https://www.drupal.org/project/hide_submit" rel="nofollow noreferrer">https://www.drupal.org/project/hide_submit</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-08-04T05:37:20.960Z
Answers.Text: nice suggestion
Answers.UserDisplayName: petednz - fuzion
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-08-04T04:35:14.280Z
Answers.LastActivityDate: 2017-08-04T04:35:14.280Z
Answers.UserDisplayName: KarinG - Semper IT
Body: <p>We process membership registration/renewal using several civicrm webforms, and at random, clients will be charged twice (so transactions will be processed twice); receipts will be sent twice, and/or there may be a duplicate webform submission.
  So both errors happen - about 90% goes well, but from my examples</p>
  
  <ul>
  <li>2 registrations have 1 submission with 2 receipts </li>
  <li>2 registrations  have 2 submissions with 1 receipt </li>
  <li>10 registrations have 2 submissions and 2 receipts ('doubleclick')</li>
  <li>1 registration has 2 submissions and 3 receipts</li>
  </ul>
  
  <p>I see no pattern. I can't find log messages about this.</p>
  
  <p>It seems to happen with all those forms; on each form, the membership type is selected in the civicrm tab of the webform; the membership fee in the membership subtab is unchecked; the contribution amount om the contribution subtab is unchecked. The underlying payment pages have no amounts configured. So civicrm_webform should get the amount from the membership type definition in CiviCRM (right ? looks that way). </p>
  
  <p>They are all multistep forms, with the payment section at the end. I'm not caching results between steps, because that can break the payment sections javascript on reload.</p>
  
  <p>We've been going through some updates, and I don't know when this started. Right now the box is shiny and uptodate.</p>
  
  <p>It seems like a timing issue; or forked threads going wild, like communication with the mailserver or payment api. Can that be ? </p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-08-04T00:21:43.603Z
Comments.Text: Have you ruled out double clicking on the Submit button?
Comments.UserDisplayName: petednz - fuzion
Tags: <drupal><civimember><webform-civicrm><4.7>
Title: webform membership : duplicate transaction & receipts and/or submissions
ThreadText: # webform membership : duplicate transaction & receipts and/or submissions
  
  (Asked by: username_0 on 2017-08-03)
  
  We process membership registration/renewal using several civicrm webforms, and at random, clients will be charged twice (so transactions will be processed twice); receipts will be sent twice, and/or there may be a duplicate webform submission.
  So both errors happen - about 90% goes well, but from my examples
  
  * 2 registrations have 1 submission with 2 receipts
  * 2 registrations have 2 submissions with 1 receipt
  * 10 registrations have 2 submissions and 2 receipts ('doubleclick')
  * 1 registration has 2 submissions and 3 receipts
  
  I see no pattern. I can't find log messages about this.
  
  It seems to happen with all those forms; on each form, the membership type is selected in the civicrm tab of the webform; the membership fee in the membership subtab is unchecked; the contribution amount om the contribution subtab is unchecked. The underlying payment pages have no amounts configured. So civicrm\_webform should get the amount from the membership type definition in CiviCRM (right ? looks that way).
  
  They are all multistep forms, with the payment section at the end. I'm not caching results between steps, because that can break the payment sections javascript on reload.
  
  We've been going through some updates, and I don't know when this started. Right now the box is shiny and uptodate.
  
  It seems like a timing issue; or forked threads going wild, like communication with the mailserver or payment api. Can that be ?
  
  **Tags:** drupal, civimember, webform-civicrm, 4.7
  
  > **Comments:**
  > **username_1**: Have you ruled out double clicking on the Submit button?  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2017-08-04. Score: 3
  
  My first thought is (similar to what Pete's suggesting) to try:
  <https://www.drupal.org/project/hide_submit>
  
  > **Comments:**
  > **username_1**: nice suggestion  
  
  ---
  
  