tags
.
<html>
<head>
<title class="a b" other="x">Title of the document</title>
</head>
<body>
The content of the document......
</body>
</html>
.
<html>
<head>
<title class="a b" other="x">Title of the document</title>
</head>
<body>
The content of the document......
</body>
</html>
.

un-closed tags
.
<div class="a">
<div class="b">
.
<div class="a">
<div class="b">
</div></div>
.

xtag
.
 <img src="img_girl.jpg" alt="Girl in a jacket" width="500" height="600"/>
.
 <img src="img_girl.jpg" alt="Girl in a jacket" width="500" height="600"/>
.

data
.
a
.
a
.

declaration
.
<!DOCTYPE html>
.
<!DOCTYPE html>
.

process information
.
<?xml-stylesheet ?>
.
<?xml-stylesheet ?>
.

entities
.
&amp;

&#123;
.
&amp;

&#123;
.

comments
.
<!--This is a comment. Comments are not displayed in the browser
-->
.
<!--This is a comment. Comments are not displayed in the browser
-->
.

image
.
<img src="img/fun-fish.png" alt="fishy" class="bg-primary mb-1" width="200px">
<img src="img/fun-fish.png" alt="fishy" class="bg-primary mb-1" width="300px">
.
<img src="img/fun-fish.png" alt="fishy" class="bg-primary mb-1" width="200px">
<img src="img/fun-fish.png" alt="fishy" class="bg-primary mb-1" width="300px">
.
