I have a php file tab.php which is creating tabs.The code of tab.php is:
<ul id="tabs">
<?php
$tab=' ';
if($tab=='') $tab='setup';
//$tab=$_REQUEST['tab'];
         if($tab=='setup'){ ?>
        <li><b><span>Setup</span></b></li>
        <?php 
        }else{ ?>
        <li><a href="?tab=setup"><span>Setup</span></a></li>
        <?php } ?>
        <?php if($tab=='options'){ ?>
        <li><b><span>Options</span></b></li>
        <?php }else{ ?>
        <li><a href="?tab=options"><span>Options</span></a></li>
        <?php } ?>
        <?php if($tab=='questions'){ ?>
        <li><b><span>Questions</span></b></li>
        <?php }else{ ?>
        <li><a href="?tab=questions"><span>Questions</span></a></li>
        <?php } ?>
        <?php if($tab=='flow'){ ?>
        <li><b><span>Flow</span></b></li>
        <?php }else{ ?>
        <li><a href="?tab=flow"><span>Flow</span></a></li>
        <?php } ?>
   </ul>
<div style="clear:both; background-color:#edcb27; height:0px; overflow:hidden;"></div>    
<div style="border:solid 3px #edcb27; background-color:#edcb27; padding:10px; font-family:Verdana, Geneva, sans-serif; font-size:11px;">
<label>Edit Mode</label>
<label>dfhfghj</label> 
I have four php files namely setup.php,options.php,question.php and test.php.What I want is when I click on setup tab setup.php should open.When I click on option.php then my option.php should open and so on.Initially setup.php should be visible.So where should I include my all four php files so that particular php file should be open when clicking on tab?