Monkeylib HTML
https://github.com/gigamonkey/monkeylib-html

monleylib-html is a library from Peter Seibel of Practical Common Lisp fame. It seems to be an implementation of HTML generation library described in the last two chapters of "Practical Common Lisp". 

(ql:quickload '(:monkeylib-html :parenscript))

(defpackage monkeylib-examples
  (:use :cl :monkeylib-html))

Emit HTML to standard output: 

(with-html-output (*standard-output*)
  (html
    ((:body :id "a" :onclick "javascript: alert(1)")
     (:h1 "Hello"))))

<body id='a' onclick='javascript: alert(1)'>
    <h1>Hello</h1>
</body>

Helpers for standard output and string: 

(defmacro htmlout (&body body)
  `(with-html-output (*standard-output* :pretty t)
     (html ,@body)))

(defmacro htmlstr (&body body)
  `(with-output-to-string (out)
     (with-html-output (out :pretty t)
       (html ,@body))))

HTML5 preamble

(define-html-macro :html5 (&attributes attrs &body body)
  `(:progn
     (:noescape (:format "<!DOCTYPE html>"))
     (:newline)
     ((:html ,@attrs)
       ,@body)))

(htmlout
  ((:html5 :lang "en")
   (:h1 "Yay! HTML5")))

<!DOCTYPE html>
<html lang='en'>
    <h1>Yay! HTML5</h1>
</html>

Parenscript

(define-html-macro :ps (&body body)
  `(:noescape (:print (ps:ps ,@body))))

(htmlout
  (:html5
   (:head
    (:script
     (:ps (defun greet () (alert "Hello, world!")))))
   (:body
    ((:button :onclick (:ps (greet))) "Click me!"))))

<!DOCTYPE html>
<html>
    <head>
        <script>function greet() {
    __PS_MV_REG = [];
    return alert('Hello, world!');
};</script>
    </head>
    <body>
        <button onclick='greet();'>Click me!</button>
    </body>
</html>

Components

TODO.