Source code for https://formidable-masterminds.com/disable-copying-email-address-into-email-confirmation-field/

disable_email_confirmation_copy.js

<script>

/* disables copy and paste */
document.getElementById("field_conf_29yf4d2").addEventListener('paste', e => e.preventDefault());

/* disables drag and drop */
document.getElementById("field_conf_29yf4d2").addEventListener('drop', e => e.preventDefault());
    
/* disables browser autocomplete */
document.getElementById("field_conf_29yf4d2").addEventListener('autocomplete', e => e.preventDefault());

</script>