_relToAbs = function( href ) {
	// Assign to a link on the original page so the browser will do all the
	// hard work of figuring out where the file actually is
	_link.href = href;
	var linkHost = _link.host;

	// IE doesn't have a trailing slash on the host
	// Chrome has it on the pathname
	if ( linkHost.indexOf('/') === -1 && _link.pathname.indexOf('/') !== 0) {
		linkHost += '/';
	}

	return _link.protocol+"//"+linkHost+_link.pathname+_link.search;
}
Convert a URL from a relative to an absolute address so it will work
correctly in the popup window which has no base URL.

@param  {string} href URL