How can PHP developers ensure that there is no output to the browser before using the "header" function for redirection?

To ensure that there is no output to the browser before using the "header" function for redirection in PHP, developers can use output buffering. This allows all output to be stored in a buffer until the script has finished executing, preventing any premature output that could interfere with header redirection.

<?php
ob_start(); // Start output buffering

// Perform any PHP logic here

// Redirect using header function
header("Location: new_page.php");

ob_end_flush(); // Flush the output buffer and send the headers
exit; // Ensure no further code is executed after redirection
?>