var link = decodeURI( window.location.href );
For example
decodeURI("http://example.com/?foo=g%C4%99%C5%9B") === "http://example.com/?foo=gęś";
Edit: what you see in the browser's URL bar isn't always exactly what a valid URI should look like. The browser handles it transparently so the user can see readable text and type any character, but the character set in a valid URI is very limited (digits, letters and a few symbols), and everything else needs to be encoded using "percent encoding". https://www.rfc-editor.org/rfc/rfc3986#section-2