Why CodeIgniter put the input hidden fields in a div display:none

[eluser]pierrehs[/eluser]
Hello,
I find the hidden forms fields in a div style="display:none"

For example for the security token

Code:

<div>
&lt;input type="hidden" name="csrf_test_name" value="b850b6655768640df3e2b887yobpgh79"&gt;
</div>

I want to know the reason, because in any case, all fields of type hidden are not visible.

Thank you.