Having trouble using index as my only URL using Php - php

Question

I'm learning and I need my index to run my pages instead of the links using php if statements and I'm missing something in my code. It just runs my header over and over again.
my if statements:
<?php
if (!isset($_GET['page']))
{
require('index.php');
}
else if ($_GET['page'] == 'aboutus') {
if (!isset($_GET['action'])) {
require('aboutus.php');
} else if ($_GET['action'] == 'store') {
require('store.php');
} else if ($_GET['action'] == 'contactus') {
require('contactus.php');
}
else
{
require('index.php');
}
}
else
{
require('index_.php');
}
?>
My nav bar:
<ul class="nav">
<li>Home</li>
<li>About</li>
<li>Current Items</li>
<li>Contact Us</li>
</ul>
I know I'm missing something, I'm just not sure what.

Answer 1

If I understood correctly that you wish to load a new file based upon the querystring parameter page ( it is unclear where the querystring parameter action comes from or how it is used ) then perhaps this might help.
<?php
/* set a variable for the querystring parameter "page" */
$page=isset( $_GET['page'] ) ? filter_input( INPUT_GET, 'page', FILTER_SANITIZE_STRING ) : false;
if( !$page ) $file='index';
else {
$pages=array(/* possible files to include */
'aboutus','store','contactus'
);
/* ensure user supplied GET variable is in desired format */
$page = strtolower( trim( pathinfo( $page, PATHINFO_FILENAME ) ) );
/* Find page in array of pages - or use default "index" */
if( in_array( $page, $pages ) )$file = $pages[ array_search( $page, $pages ) ];
else $file = 'index';
}
require sprintf( '%s.php', $file );
?>
The above could be simplified slightly like so:
<?php
/* set a variable for the querystring parameter "page" */
$page=isset( $_GET['page'] ) ? filter_input( INPUT_GET, 'page', FILTER_SANITIZE_STRING ) : false;
$pages=array(/* possible files to include */
'aboutus','store','contactus'
);
/* ensure user supplied GET variable is in desired format */
$page = strtolower( trim( pathinfo( $page, PATHINFO_FILENAME ) ) );
/* Find page in array of pages - or use default "index" */
if( in_array( $page, $pages ) )$file = $pages[ array_search( $page, $pages ) ];
else $file = 'index';
require sprintf( '%s.php', $file );
?>

Answer 2

why is that??? you can implement Single Page Application that url only change ater hashTag like :
link.url/index#about-us
link.url/index#store
and ...
about your problem , after require your code continueus , you must die; after each require to finish loop. just made it a little prettier.
<?php
if (!isset($_GET['page'])) {
require('index.php');die;
}
if ($_GET['page'] != 'aboutus') {
require('index_.php');die;
}
// where is your action variable in your code?????????????
// it's about us
if (!isset($_GET['action'])) {
require('aboutus.php');die;
}
switch ($_GET['action']) {
case 'store':
require('store.php');die;
break;
case 'contactus':
require('contactus.php');die;
break;
default:
die("route is not defined");
break;
}
?>