Sometimes we need to include or load
wp-load.php file to get access from WordPress core & theme function action and if there has no way to get access from
function.php file to include/require function. Basically this is really essential when we write a ajax method that need to get & return value from WordPress.
So here is the code where you can include wp-load.php file anywhere in WordPress theme:
$parse_uri = explode( 'wp-content', $_SERVER['SCRIPT_FILENAME'] ); require( $parse_uri . 'wp-load.php' );