From a8ba821b5bd8dce36de6fa5bca9a8e6d39d8e609 Mon Sep 17 00:00:00 2001
From: Taco de Wolff <tacodewolff@gmail.com>
Date: Thu, 13 Sep 2018 15:50:26 +1200
Subject: [PATCH] Keep empty value attr on radio input, fixes #226

---
 html/html.go      | 15 ++++++++++++---
 html/html_test.go |  2 ++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/html/html.go b/html/html.go
index 73a03e1363..2fdc454baa 100644
--- a/html/html.go
+++ b/html/html.go
@@ -312,7 +312,17 @@ func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]st
 					if attrs[0] != nil && attrs[1] != nil {
 						attrs[1].Text = nil
 					}
-				}
+				} else if t.Hash == html.Input {
+                    attrs := tb.Attributes(html.Type, html.Value)
+                    if t, value := attrs[0], attrs[1]; t != nil && value != nil {
+                        isRadio := parse.EqualFold(t.AttrVal, []byte("radio"))
+                        if !isRadio && len(value.AttrVal) == 0 {
+                            value.Text = nil
+                        } else if isRadio && parse.EqualFold(value.AttrVal, []byte("on")) {
+                            value.Text = nil
+                        }
+                    }
+                }
 
 				// write attributes
 				htmlEqualIdName := false
@@ -343,8 +353,7 @@ func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]st
 						attr.Hash == html.Lang ||
 						attr.Hash == html.Name ||
 						attr.Hash == html.Title ||
-						attr.Hash == html.Action && t.Hash == html.Form ||
-						attr.Hash == html.Value && t.Hash == html.Input) {
+						attr.Hash == html.Action && t.Hash == html.Form) {
 						continue // omit empty attribute values
 					}
 					if attr.Traits&caselessAttr != 0 {
diff --git a/html/html_test.go b/html/html_test.go
index 077edcc0fc..dbd11eee32 100644
--- a/html/html_test.go
+++ b/html/html_test.go
@@ -51,6 +51,8 @@ func TestHTML(t *testing.T) {
 		{`</span >`, `</span>`},
 		{`<meta name=viewport content="width=0.1, initial-scale=1.0 , maximum-scale=1000">`, `<meta name=viewport content="width=.1,initial-scale=1,maximum-scale=1e3">`},
 		{`<br/>`, `<br>`},
+        {`<input type="radio" value="">`, `<input type=radio value>`},
+        {`<input type="radio" value="on">`, `<input type=radio>`},
 
 		// increase coverage
 		{`<script style="css">js</script>`, `<script style=css>js</script>`},