Cookie Setting troubles in PHP

I was trying to determine why the value for a cookie is not reflecting on my page.

Here are some of other developers say you should now in implementing cookies:

1. It has to be on top before any code is generated by the page
2. Cookie will not reflect on the same page when you set it.  It will reflect on the next loading of the page.

2nd one is true.  The first one also seems to be true, since no value is placed when I placed the code in the middle and after html codes have been rendered.

Here are the links to those recommendations:

http://stackoverflow.com/questions/7958930/cookie-page-counter-in-php

http://php.about.com/od/advancedphp/qt/php_cookie.htm

There is a problem with the cookie when the mobile browser is never closed.  I had my browser open in the background.  Even when I set the cookie to expire in 30 mins.  It does not happened, since the browser still reads the value even beyond expire date.