diff --git a/parser/attribute.go b/parser/attribute.go
index 42b1753..f417d2b 100644
--- a/parser/attribute.go
+++ b/parser/attribute.go
@@ -2,6 +2,7 @@ package parser
 
 import (
 	"bytes"
+	"io"
 	"strconv"
 
 	"github.com/yuin/goldmark/text"
@@ -227,7 +228,7 @@ func parseAttributeString(reader text.Reader) ([]byte, bool) {
 	return nil, false
 }
 
-func scanAttributeDecimal(reader text.Reader, w *bytes.Buffer) {
+func scanAttributeDecimal(reader text.Reader, w io.ByteWriter) {
 	for {
 		c := reader.Peek()
 		if util.IsNumeric(c) {
diff --git a/parser/html_block.go b/parser/html_block.go
index c796354..a1f3338 100644
--- a/parser/html_block.go
+++ b/parser/html_block.go
@@ -134,7 +134,7 @@ func (b *htmlBlockParser) Open(parent ast.Node, reader text.Reader, pc Context)
 		isCloseTag := match[2] > -1 && bytes.Equal(line[match[2]:match[3]], []byte("/"))
 		hasAttr := match[6] != match[7]
 		tagName = strings.ToLower(string(line[match[4]:match[5]]))
-		_, ok := allowedBlockTags[strings.ToLower(string(tagName))]
+		_, ok := allowedBlockTags[tagName]
 		if ok {
 			node = ast.NewHTMLBlock(ast.HTMLBlockType6)
 		} else if tagName != "script" && tagName != "style" && tagName != "pre" && !ast.IsParagraph(last) && !(isCloseTag && hasAttr) { // type 7 can not interrupt paragraph