FalkeynScript

falkeyn.js

// ==UserScript==
// @name         FalkeynScript
// @match        *
// ==/UserScript==

/* jshint multistr: true */

(function() {
    var css = '\
<style>\
.falkeyn { font-style: italic; margin: 1em; }\
</style>';
    
    var html = '\
<div class="falkeyn">Hi, falkeyn :)</div>\
';

    document.body.innerHTML = css + html + document.body.innerHTML;
    
    console.log('Tampering works!');
})();