setAttribute error when using with Typekit in Safari

[benknight]

I found an extreme edge case bug but nevertheless it's something I believe could effect many users of this project.

It turns out Typekit's code snippet overrides Element.prototype.setAttribute as follows:

t.setAttribute = function(e, r, i, l) {
        r.match(s) && (i = new XMLHttpRequest,
        i.open("GET", r, !0),
        i.onreadystatechange = function() {
            4 === i.readyState && (l = i.responseText,
            l !== o && (n[a] = l))
        }
        ,
        i.send(null ),
        t.setAttribute = u,
        o) || u.apply(this, arguments)
    }

And in the Tab.js component we have this:

node.setAttribute('tabindex', 0);

Which is causing the following error, only in Safari:

TypeError: r.match is not a function. (In 'r.match(s)', 'r.match' is undefined)

This is happening because the "r" argument of Typekit's custom setAttribute is expected to be a string, however it's receiving an integer 0, which has no match function.

So the fix is just change the line above to:

node.setAttribute('tabindex', '0');