if($var == "abc" || $var == "def" || ...)
{
echo "true";
}
<?php
$thisuri = $_SERVER['REQUEST_URI'];
$thisarray=array(
'/url1/',
'/url2/',
'/url3/',
'/url4/',
'/url5/'
);
if ( in_array($thisuri,$thisarray) ) { ?>
<!-- Your HTML code goes here -->
<!-- Pixel --><!-- /Pixel -->
<?php }?>