Why does this code make my screen go blank in admin when I put it in functions.php?

问题

When publishing content or changing any settings in the admin, the screen goes blank, I found that it's due to this code in my functions.php file. Is there something wrong with it?

<?php
if ( function_exists('register_sidebar') ) {
register_sidebar(array(
    'name'=> 'Footer',
    'id' => 'footer',
    'before_widget' => '',
    'after_widget' => '',
    'before_title' => '<div class="title">',
    'after_title' => '</div>'
));
register_sidebar(array(
    'name'=> 'Right-Sidebar',
    'id' => 'rightsidebar',
    'before_widget' => '<div class="white-bar">',
    'after_widget' => '</div>',
    'before_title' => '<div class="title">',
    'after_title' => '</div>'
));
register_sidebar(array(
    'name'=> 'Ads',
    'id' => 'ads',
    'before_widget' => '',
    'after_widget' => '',
    'before_title' => '<div class="title">',
    'after_title' => '</div>'
));
}
?>

Fairly new to this, so details would be excellent!

回答1:

I know this may not be the answer, but I have run into this problem before, and on several occasions it was some extra whitespace at the top or bottom of the functions.php file.

Maybe check that if nothing else works.

It could be a number of things, but I always check the easiest thing to fix first!

回答2:

In my WP code, I don't include brackets {} around the if statement. My functional code looks like:

if ( function_exists('register_sidebar') )
register_sidebar(array('name'=>'sidebar1',
    'before_widget' => '',
    'after_widget' => '',
    'before_title' => '<h2>',
    'after_title' => '</h2>',
));
register_sidebar(array('name'=>'sidebar2',
    'before_widget' => '',
    'after_widget' => '',
    'before_title' => '<h2>',
    'after_title' => '</h2>',
));

回答3:

Un-needed spacing in the functions.php file was causing this.

来源：https://stackoverflow.com/questions/8881569/why-does-this-code-make-my-screen-go-blank-in-admin-when-i-put-it-in-functions-p