What potential issue can arise if HTML code is placed before session_start() in PHP?

Placing HTML code before session_start() in PHP can cause a "headers already sent" error because session_start() needs to send headers to start a session, and any output before that prevents headers from being sent. To solve this issue, make sure to call session_start() before any HTML code or output is sent to the browser. 

<?php
session_start();

// HTML code and other PHP code here
?>

Keywords

HTML session_start() PHP headers cookies

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