Try it Yourself: XML Validator

XML Validator

<!DOCTYPE html>
<html>
<body>

<pre>
&lt;!-- Well-formed: single root, properly nested, closed tags --&gt;
&lt;order id="1042"&gt;
  &lt;customer&gt;Priya Shah&lt;/customer&gt;
  &lt;items&gt;
    &lt;item qty="2"&gt;Notebook&lt;/item&gt;
    &lt;item qty="1"&gt;Pen &amp;amp; Pencil Set&lt;/item&gt;
  &lt;/items&gt;
&lt;/order&gt;

&lt;!-- Malformed: overlapping tags and an unescaped ampersand --&gt;
&lt;!--
&lt;order id="1042"&gt;
  &lt;customer&gt;Priya Shah
  &lt;items&gt;
    &lt;item qty="2"&gt;Notebook&lt;/customer&gt;
    &lt;item qty="1"&gt;Pen &amp; Pencil Set&lt;/item&gt;
  &lt;/items&gt;
&lt;/order&gt;
--&gt;
</pre>

</body>
</html>

<!DOCTYPE html>
<html>
<body>

<pre>
&lt;!-- Well-formed: single root, properly nested, closed tags --&gt;
&lt;order id="1042"&gt;
  &lt;customer&gt;Priya Shah&lt;/customer&gt;
  &lt;items&gt;
    &lt;item qty="2"&gt;Notebook&lt;/item&gt;
    &lt;item qty="1"&gt;Pen &amp;amp; Pencil Set&lt;/item&gt;
  &lt;/items&gt;
&lt;/order&gt;

&lt;!-- Malformed: overlapping tags and an unescaped ampersand --&gt;
&lt;!--
&lt;order id="1042"&gt;
  &lt;customer&gt;Priya Shah
  &lt;items&gt;
    &lt;item qty="2"&gt;Notebook&lt;/customer&gt;
    &lt;item qty="1"&gt;Pen &amp; Pencil Set&lt;/item&gt;
  &lt;/items&gt;
&lt;/order&gt;
--&gt;
</pre>

</body>
</html>