Why does the placement of session_start() matter in PHP code?

The placement of session_start() matters in PHP code because it needs to be called before any output is sent to the browser. If session_start() is called after any HTML or whitespace, it can cause errors such as "headers already sent" because session_start() sends headers to the browser. To solve this issue, make sure to call session_start() at the beginning of the PHP script before any other code. 

<?php
session_start();

// Rest of the PHP code goes here
?>

Keywords

session_start PHP code placement session variables session management

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