How to create pop up window for login page
1)use this module
https://www.drupal.org/project/modal_forms

2)create a block and put this code in it :

 &lt;?php
global $user;
 global $base_url;
if($user-&gt;uid == '0')
{ 
?&gt;
&lt;a class="ctools-use-modal" href="&lt;?php print $base_url; ?  &gt;/modal_forms/nojs/login"&gt;Login&lt;/a&gt;
 &lt;?php
}
else
 {
 echo '&lt;p&gt;&lt;a href="'.$base_url.'/user/logout"&gt;Logout&lt;/a&gt;&lt;/p&gt;';
}
?&gt;