How can headers already sent errors be prevented in PHP scripts?

Headers already sent errors in PHP scripts can be prevented by ensuring that no output is sent to the browser before calling functions like header() or setcookie(). To prevent this issue, make sure to place all header-related functions at the beginning of the script, before any HTML or whitespace. Additionally, using output buffering functions like ob_start() can help prevent headers already sent errors by capturing the output before it is sent to the browser. 

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

// Place header-related functions at the beginning of the script
header('Location: https://www.example.com');
exit();

ob_end_flush(); // Flush the output buffer
?>

Keywords

output buffering ob_start ob_end_flush ob_clean header

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