diff --git a/lib/html_tag.js b/lib/html_tag.js
index 173f9077..85510fa7 100644
--- a/lib/html_tag.js
+++ b/lib/html_tag.js
@@ -6,7 +6,10 @@ function htmlTag(tag, attrs, text) {
   var result = '<' + tag;
 
   for (var i in attrs) {
-    if (attrs[i]) result += ' ' + i + '="' + attrs[i] + '"';
+    if (
+      attrs[i] !== undefined
+      && attrs[i] !== null
+    ) result += ' ' + i + '="' + attrs[i] + '"';
   }
 
   result += text == null ? '>' : '>' + text + '</' + tag + '>';
diff --git a/test/scripts/html_tag.js b/test/scripts/html_tag.js
index b079b81e..4bf9182b 100644
--- a/test/scripts/html_tag.js
+++ b/test/scripts/html_tag.js
@@ -27,6 +27,34 @@ describe('htmlTag', function() {
     }, 'My blog').should.eql('<a href="http://zespia.tw">My blog</a>');
   });
 
+  it('tag + empty ALT attr', function() {
+    htmlTag('img', {
+      src: 'http://placekitten.com/200/300',
+      alt: ''
+    }).should.eql('<img src="http://placekitten.com/200/300" alt="">');
+  });
+
+  it('passing a zero as attribute', function() {
+    htmlTag('a', {
+      href: 'http://zespia.tw',
+      tabindex: 0
+    }, 'My blog').should.eql('<a href="http://zespia.tw" tabindex="0">My blog</a>');
+  });
+
+  it('passing a null alt attribute', function() {
+    htmlTag('a', {
+      href: 'http://zespia.tw',
+      alt: null
+    }, 'My blog').should.eql('<a href="http://zespia.tw">My blog</a>');
+  });
+
+  it('passing a undefined alt attribute', function() {
+    htmlTag('a', {
+      href: 'http://zespia.tw',
+      alt: undefined
+    }, 'My blog').should.eql('<a href="http://zespia.tw">My blog</a>');
+  });
+
   it('tag is required', function() {
     try {
       htmlTag();