Wetseal website is not "certified" and the certificate does not match the site?

When I go to the Wetseal website, it works just fine. I can add items to my basket without a problem. But if I want to edit my basket something comes up that I can click "show certificate" "cancel" or "ok" I clicked show certificate and I get a warning that its not certified and the certificate does not match the site. What is this? Is it safe to use my credit card and purchase online?