How can echoing content before using the header function in PHP cause issues, and what is the correct approach?

Echoing content before using the header function in PHP can cause issues because headers must be sent before any actual output is sent to the browser. To fix this issue, make sure to call the header function before any output, such as HTML, text, or whitespace, is echoed or printed to the browser. 

<?php
// Correct approach: set header before any output
header('Location: https://www.example.com');
exit;

Keywords

echo header function output buffering headers already sent ob_start

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