Here’s a demo which has working HTML links.
https://run.pavlovia.org/pavlovia/survey/?surveyId=18c1a56c-1448-4db9-aad9-19e06dc7859d
The first link gives a warning (Leave or Cancel).
The second link avoids this by including target="_blank" to open a new tab i.e.
<a href="https://moryscarter.com/vespr/grademailer.php" target="_blank">VESPR Grademailer</a>