header(Location) but with keeping the old url?

Is the possible to make an header(Location: /404.php); for example but to keep in the url the same old page... like /denise for example,etc?

 

yes, do header( 'HTTP/1.0 404 Error' ); instead (i.e. don't send a Location: redirect)

 

Yes, but some browsers will put their own add when they see an 404 status

 

you could do something like this.

// start output buffer
ob_start();

// some code here 

// somewhere you need to indicate if you want to display a 404 or not
// you could do it like this.

if ($some_variable == 2) {
   $error = 404;
}

// check if you want to display a 404 on same url
if ($error == 404) {

  // empty output buffer
  ob_clean();

  // include 404 error page
  include_once('404.php');
  
  // stop executing
  exit;

}

PHP:

Haven't tested it so not sure if this would work but in theory it should.