I believe that a meta refresh does not leave a trace of a referrer <meta http-equiv="refresh" content="0; url=http://www.example.com">
The thing here though, is getting it from an onclick (a
) element, so you should, AFAIK, be able to do something like:
<a onclick="mask('http://www.example.com/')">Click me</a>
function mask(url) {
var meta = document.createElement("meta");
meta.setAttribute("http-equiv", "refresh");
meta.setAttribute("content", "0; url=" + url);
}
Disclaimer: untested