 <p>Some characters in Url are reserved characters and have special meaning. To use them in Url parameters they must be properly <a href="http://en.wikipedia.org/wiki/Percent-encoding" rel="nofollow">URL encoded</a>.</p> <pre><code>/?link=http://a-link.com </code></pre> <p>is not a proper URL. It should be:</p> <pre><code>/?link=http%3A%2F%2Fa-link.com </code></pre>