Generate random activation code in PHP : <p>How to generate random activation code based on current datetime and username in PHP.</p>

<p>The return value should be like this, i.e: </p>

<p>201605021955Username</p>

<pre><code>function getActivationCode($username){
$activationCode = "";        

 ....

return activationCode;
}
</code></pre>
