How to Redirect Page in PHP after a few seconds without meta http-equiv=REFRESH CONTENT=time

Header tags are sent on page load, to the browser, so that it can quickly redirect the user to the desired page without bothering to render it or even load it into the history. As such, you can't call a redirect once the page has already loaded, as the headers have already been dealt with.

You can instead perform this with:

header( "refresh:5;url=wherever.php" );

Which basically sets the <meta> tag in the headers of the page itself, meaning you don't need to write the tag out.