How can the order of code execution be affected when using header functions in PHP scripts?

When using header functions in PHP scripts, the order of code execution can be affected because headers must be sent before any actual output is sent to the browser. To ensure proper order, it's important to set headers before any output is generated, including whitespace. One common solution is to move all header functions to the very beginning of the script before any HTML or PHP code. 

<?php
// Set headers at the beginning of the script
header("Content-Type: text/html");
header("Cache-Control: no-cache");

// Start session
session_start();

// Rest of the PHP script
echo "Hello, World!";
?>

Keywords

header functions code execution PHP scripts order affect

Related Questions