Why I have to call 'exit' after redirection through header('Location..') in PHP?

Question

You know that if you want to redirect an user in PHP you can use the header function:

header(\'Location: http://smowhere.com\');

It is also

Answer 1

PHP Code after a header() will be run. Sometimes, that is required though, as the example on php.net shows. To make sure it's not, you end the program flow entirely.