// ==UserScript==
// @name         AO3 Remove Double-Spacing
// @namespace    ao3-remove-double-spacing
// @version      1.0
// @description  Removes awkward double spaces between paragraphs on AO3.
// @author       yuube
// @match        http*://*.archiveofourown.org/works/*
// @grant        none
// @downloadURL none
// ==/UserScript==

function hideEmptyElement (el) {
   var content = el.textContent && el.textContent.trim().replace(' ', '')
   if (!content) {
       el.style.display = 'none'
   }
}

var chapters = document.querySelector('#chapters')

// Remove empty paragraphs
chapters.querySelectorAll('p').forEach(hideEmptyElement);

// Remove empty divs
chapters.querySelectorAll('div').forEach(hideEmptyElement);

// Remove any other empty elements (won't catch many cases)
chapters.querySelectorAll(':empty').forEach(hideEmptyElement);

// Remove excessive line breaks (replaces 2 or more <br />s with one)
chapters.innerHTML = chapters.innerHTML.replace(/(<br\s*\/?>){3,}/gi, '<br>');