From 863c6f9b1d07e8751fffb117088a5d0b5cef681c Mon Sep 17 00:00:00 2001
From: AC <ac@fabtek.cn>
Date: Tue, 20 Oct 2026 14:14:46 +0800
Subject: [PATCH] Preserve form feeds in quoted attribute values

---
 src/HTML5/Parser/Tokenizer.php |  2 +-
 test/HTML5/Html5Test.php       | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/HTML5/Parser/Tokenizer.php b/src/HTML5/Parser/Tokenizer.php
index 653903c..17a3052 100644
--- a/src/HTML5/Parser/Tokenizer.php
+++ b/src/HTML5/Parser/Tokenizer.php
@@ -567,7 +567,7 @@ protected function attributeValue()
      */
     protected function quotedAttributeValue($quote)
     {
-        $stoplist = "\f" . $quote;
+        $stoplist = $quote;
         $val = '';
 
         while (true) {
diff --git a/test/HTML5/Html5Test.php b/test/HTML5/Html5Test.php
index 0fd307e..3c267e2 100644
--- a/test/HTML5/Html5Test.php
+++ b/test/HTML5/Html5Test.php
@@ -38,6 +38,38 @@ protected function cycleFragment($fragment)
         return $out;
     }
 
+    public function testFormFeedsInQuotedAttributes()
+    {
+        foreach (array('"', "'") as $quote) {
+            $value = "\fbefore &amp;\f after\f";
+            $html = '<img alt=' . $quote . $value . $quote . ' src="foo.png">';
+            $expected = "\fbefore &\f after\f";
+
+            $document = $this->html5->loadHTML($this->wrap($html));
+            $image = $document->getElementsByTagName('img')->item(0);
+            $this->assertSame($expected, $image->getAttribute('alt'));
+            $this->assertSame('foo.png', $image->getAttribute('src'));
+            $this->assertSame(2, $image->attributes->length);
+            $this->assertEmpty($this->html5->getErrors());
+
+            $fragment = $this->html5->loadHTMLFragment($html);
+            $this->assertSame($expected, $fragment->firstChild->getAttribute('alt'));
+            $serialized = $this->html5->saveHTML($fragment);
+            $reparsed = $this->html5->loadHTMLFragment($serialized);
+            $this->assertSame($expected, $reparsed->firstChild->getAttribute('alt'));
+            $this->assertSame('foo.png', $reparsed->firstChild->getAttribute('src'));
+            $this->assertEmpty($this->html5->getErrors());
+        }
+    }
+
+    public function testFormFeedStillSeparatesUnquotedAttributes()
+    {
+        $fragment = $this->html5->loadHTMLFragment("<img alt=before\fsrc=foo.png>");
+        $this->assertSame('before', $fragment->firstChild->getAttribute('alt'));
+        $this->assertSame('foo.png', $fragment->firstChild->getAttribute('src'));
+        $this->assertEmpty($this->html5->getErrors());
+    }
+
     public function testImageTagsInSvg()
     {
         $html = '<!DOCTYPE html>