To verify that the user is indeed a human, a simple yet effective method is to use a visual CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). The process involves pressing and holding down on a button or image for a specified duration.
The primary purpose of this test is to prevent automated programs from interacting with the website. By requiring users to complete a manual task, it ensures that only genuine humans can access the site’s features and functionality.
Source: https://www.sfgate.com/bayarea/article/bay-area-exposed-measles-stores-20353585.php