CAPTCHA challenge

Example of a CAPTCHA challenge on a form


What exactly is a CAPTCHA challenge?

CAPTCHA challenges are designed to authenticate whether or not a user filling out a form is human. In turn, this can help reduce or even eliminate spam submissions received through the form.

At the University of Ottawa, we have accepted under certain conditions the use of Google's "NoCAPTCHA reCAPTCHA" test, which requires that the user simply checkmark a box that says "I'm not a robot", as long as accessibility requirements are met.

Is Google's NoCAPTCHA reCAPTCHA accessible?

By and large, reCAPTCHA is the most widely used CAPTCHA challenge on the web at the moment and Google itself has taken many steps to make reCAPTCHA as accessible as possible (read Google's statement on reCAPTCHA's accessibility). Independent analyses (e.g. reCAPTCHA Accessibility reVISTED and The accessibility of Google’s No CAPTCHA) also conclude that Google's NoCAPTCHA reCAPTCHA challenge is one of the most accessible for mouse users, keyboard users and screen reader users. Our own tests confirm this.

However, there is one single reservation when it comes to the second challenge that reCAPTCHA renders if the user is deemed suspicious. Specifically, people who are deaf-blind cannot complete the second image-selection or audio challenge, as neither the visual component nor the audio component is accessible to them. For this reason, if you enable reCAPTCHA, you must provide an alternative method for users to be able to submit the information, such as by providing your department or service's contact information.

Should I enable CAPTCHA on my form?

Since reCAPTCHA adds an extra layer of difficulty to a form and since it may not be accessible to deaf-blind users, we recommend that webmasters avoid enabling CAPTCHA by default.

  • If the form is getting lightly spammed, you or your webmaster should consider using the Honeypot module instead, which is both accessible and should filter out most incoming spam.
  • If the form is getting excessively spammed, you or your webmaster may enable CAPTCHA on the form. However, you need to provide an alternative method for deaf-blind users to fill out the form. For example, it would suffice to add a line at the top of the form saying "If you cannot fill out this form and require assistance, please contact our department or service at [email address] or by phone at [phone number]."
China blocks reCAPTCHA
InformationPlease note that if your form needs to target international users from China, you should not implement reCAPTCHA on your form.

How do I add a CAPTCHA challenge to my form?


If you have deemed it necessary to add a CAPTCHA challenge to a form, follow the steps below.

  1. Navigate to Content and then click on the tab "Webforms" at the top-right.
  2. Find the form for which you wish to enable CAPTCHA. Under the "Operations" column, click on the link Components.
    1. Under this tab, add a new component with the type set to "Markup".
    2. In the Value field, add a message that provides an alternative method for providing the information. For example, add a line saying "If you cannot fill out this form and require assistance, please contact our department or service at [email address] or by phone at [phone number]."
    3. Click on the button Save component once done.
    4. Move the new component as needed and click on the button Save.
  3. Next, click on the sub-tab "Form settings" found at the top-right corner of the page.
  4. Find the CAPTCHA section and select the box "Enable CAPTCHA on this form".
  5. Click on Save configuration.


  • If you cannot see the CAPTCHA section under Form settings: This means that the "uOttawa Webforms" module is not enabled. If you do not have access to enable modules, ask your website's administrator to do it for you or open a ticket through the Service Desk Request form to ask that the Web Services team do it for you.
  • If you cannot see the CAPTCHA challenge on your form: Users with webmaster-level access or higher will not see the CAPTCHA challenge when logged in. If you wish to visualize it, either log out or open a new private (incognito) window in your browser.
» Submit feedback
  • User Guide
Back to top