PHP Header（）函数未重定向

Question

I've got a problem with the header function

if ( ! isset($_SESSION['user']) ) {

   header('Location: login.php');

}

There is no echo before the if, the page is empty!

it doesn't redirect me. I've var_dump(); 'ed something in the If statement and it worked so the if is correct.

The php version is 5.6

Answer 1

You might have outputted something to the browser before header call. First check:

• is there any html before php opening tag

• is there any whitespace before php opening tag

• is another php script included with echo before that script

• is the coding utf8 with BOM?

Those are possible reasons of your error.

Answer 2

Try this code :-

<?php
if ( ! isset($_SESSION['user']) ) {
?>
<script>
    window.location = 'login.php';
</script>
<?php
}
?>

Answer 3

您还可以执行以下操作：

echo "<script>window.location = 'login.php';</script>";

Answer 4

white space may cause the redirect change it to something like

if ( ! isset($_SESSION['user']) ) {

   header('location:login.php');

 }