diff --git a/Parsedown.php b/Parsedown.php
index 6e2a8e1..006d9db 100644
--- a/Parsedown.php
+++ b/Parsedown.php
@@ -554,13 +554,17 @@ class Parsedown
 
         $text = trim($text, ' ');
         $link = strtolower(str_replace(' ','-',$text));
+	$attr = array();
+	if (!empty($link)) {
+		$attr = array(
+                    'id' => $link,
+                );
+	}
 
         $Block = array(
             'element' => array(
                 'name' => 'h' . $level,
-                'attributes' => array(
-                    'id' => $link,
-                ),
+                'attributes' => $attr,
                 'handler' => array(
                     'function' => 'lineElements',
                     'argument' => $text,
diff --git a/test/ParsedownTest.php b/test/ParsedownTest.php
index bf40317..8112537 100755
--- a/test/ParsedownTest.php
+++ b/test/ParsedownTest.php
@@ -54,8 +54,10 @@ class ParsedownTest extends TestCase
         $this->Parsedown->setStrictMode(substr($test, 0, 6) === 'strict');
 
         $actualMarkup = $this->Parsedown->text($markdown);
+        $actualMarkup = str_replace("\r\n", "\n", $actualMarkup);
+        $actualMarkup = str_replace("\r", "\n", $actualMarkup);
 
-        $this->assertEquals($expectedMarkup, $actualMarkup);
+        $this->assertEquals(trim($expectedMarkup), trim($actualMarkup));
     }
 
     function testRawHtml()
diff --git a/test/data/atx_heading.html b/test/data/atx_heading.html
index 3b09c38..80bceea 100644
--- a/test/data/atx_heading.html
+++ b/test/data/atx_heading.html
@@ -1,13 +1,13 @@
-<h1>h1</h1>
-<h2>h2</h2>
-<h3>h3</h3>
-<h4>h4</h4>
-<h5>h5</h5>
-<h6>h6</h6>
-<p>####### not a heading</p>
-<h1>closed h1</h1>
-<h1></h1>
-<h2></h2>
-<h1># of levels</h1>
-<h1># of levels #</h1>
-<h1>heading</h1>
\ No newline at end of file
+<h1 id="h1">h1</h1>
+<h2 id="h2">h2</h2>
+<h3 id="h3">h3</h3>
+<h4 id="h4">h4</h4>
+<h5 id="h5">h5</h5>
+<h6 id="h6">h6</h6>
+<p>####### not a heading</p>
+<h1 id="closed-h1">closed h1</h1>
+<h1></h1>
+<h2></h2>
+<h1 id="#-of-levels"># of levels</h1>
+<h1 id="#-of-levels-#"># of levels #</h1>
+<h1 id="heading">heading</h1>
diff --git a/test/data/strict_atx_heading.html b/test/data/strict_atx_heading.html
index 11cf4df..c934064 100644
--- a/test/data/strict_atx_heading.html
+++ b/test/data/strict_atx_heading.html
@@ -1,13 +1,13 @@
-<h1>h1</h1>
-<h2>h2</h2>
-<h3>h3</h3>
-<h4>h4</h4>
-<h5>h5</h5>
-<h6>h6</h6>
+<h1 id="h1">h1</h1>
+<h2 id="h2">h2</h2>
+<h3 id="h3">h3</h3>
+<h4 id="h4">h4</h4>
+<h5 id="h5">h5</h5>
+<h6 id="h6">h6</h6>
 <p>####### not a heading</p>
 <p>#not a heading</p>
-<h1>closed h1</h1>
+<h1 id="closed-h1">closed h1</h1>
 <h1></h1>
 <h2></h2>
-<h1># of levels</h1>
-<h1># of levels #</h1>
\ No newline at end of file
+<h1 id="#-of-levels"># of levels</h1>
+<h1 id="#-of-levels-#"># of levels #</h1>