The read-only expires
property of the RTCCertificate
interface returns the expiration date of the certificate.
By default a new certificate is configured with expires
set to a value of 2592000000 milliseconds, or 30 days. The expiration time cannot exceed 31536000000 milliseconds, or 365 days. It's also useful to note that browsers may further restrict the expiration time of certificates if they choose.