diff --git a/src/Dom/Document.php b/src/Dom/Document.php
index 48878088b21..4ce2dd5093b 100644
--- a/src/Dom/Document.php
+++ b/src/Dom/Document.php
@@ -541,17 +541,29 @@ private function move_invalid_head_nodes_to_body() {
* Converts a possible head[profile] attribute to link[rel=profile].
*
* The head[profile] attribute is only valid in HTML4, not HTML5.
- * So if it exists, add it to the as a link[rel=profile] and strip the attribute.
+ * So if it exists and there's no link[rel=profile], add it to the as a link[rel=profile].
*/
private function convert_head_profile_to_link() {
$profile = $this->head->getAttribute( 'profile' );
- if ( $profile ) {
- $link = $this->createElement( 'link' );
- $link->setAttribute( 'rel', 'profile' );
- $link->setAttribute( 'href', $profile );
- $this->head->appendChild( $link );
- $this->head->removeAttribute( 'profile' );
+ if ( ! $profile ) {
+ return;
}
+
+ // If there's already a head > link[rel=profile], don't create another.
+ $links = $this->head->getElementsByTagName( 'link' );
+ foreach( $links as $link ) {
+ if ( 'profile' === $link->getAttribute( 'rel' ) ) {
+ $this->head->removeAttribute( 'profile' );
+ return;
+ }
+ }
+
+ // Create a and append it to .
+ $new_link = $this->createElement( 'link' );
+ $new_link->setAttribute( 'rel', 'profile' );
+ $new_link->setAttribute( 'href', $profile );
+ $this->head->appendChild( $new_link );
+ $this->head->removeAttribute( 'profile' );
}
/**
diff --git a/tests/php/test-class-amp-dom-document.php b/tests/php/test-class-amp-dom-document.php
index f2fa7a9ba03..cb6f3383f37 100644
--- a/tests/php/test-class-amp-dom-document.php
+++ b/tests/php/test-class-amp-dom-document.php
@@ -169,6 +169,11 @@ public function data_dom_document() {
'',
'',
],
+ 'link_rel_profile_already_exists' => [
+ 'utf-8',
+ '',
+ '',
+ ],
];
}