Add paragraphs and style to HTML

text.js

(function() {
   var link = document.createElement('link'); 
   link.rel = 'stylesheet'; 
   link.href = 'style.css'; 
   document.head.appendChild(link); 
})(); 

window.onload = function() {
   document.body.innerHTML = document.body.innerHTML
      .replace(/\n\n/g, '<p>')
      .replace(/\n/g, '<br>'); 
};