<!DOCTYPE html>
<html lang="en-US">
<head>
<style>
#point:after{
content:"\00021";
}
</style>
</head>
<body>
<p>Exclamation Mark using Hexa Decimal: !</p>
<p>Exclamation Mark using HTML Code: !</p>
<p>Exclamation Mark using HTML Entity: !</p>
<p id="point">Exclamation Mark using CSS Entity: </p> </body>
</html>