new Url('//url-with-relative-protocol.co.uk/blah').toString();
// actual -> 'url-with-relative-protocol.co.uk/blah'
// expected 1 -> '//url-with-relative-protocol.co.uk/blah'
// expected 2 -> [current page's protocol] + '//url-with-relative-protocol.co.uk/blah'
(Found in IE10)