Smart Text Justifier

Justifies p and textarea tags unless they (or their parents) are centered.

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Smart Text Justifier
// @namespace    http://tampermonkey.net/
// @version      1.3
// @description  Justifies p and textarea tags unless they (or their parents) are centered.
// @author       Ȼaptain Jøhn “Søap” MacTavish
// @license      CC-BY-NC-SA-4.0
// @match        *://*/*
// @grant        none
// ==/UserScript==

(
    function()
    {
        'use strict';
    
        const JustifyTargetElements = () =>
        {
            const TargetNodes = document.querySelectorAll('p, textarea');
    
            TargetNodes.forEach
            (
                Element =>
                {
                    // Check the actual computed alignment from CSS or attributes
                    const ComputedAlignment = window.getComputedStyle(Element).textAlign;
    
                    // Only apply justification if the element is NOT centered
                    if (ComputedAlignment !== 'center')
                    {
                        Element.style.setProperty('text-align', 'justify', 'important');
                        Element.style.setProperty('text-justify', 'inter-word', 'important');
                    }
                }
            );
        };
    
        const InitializeObserver = () =>
        {
            // Initial run
            JustifyTargetElements();
    
            // Observe the body for dynamically loaded content (AJAX, infinite scroll)
            const ContentObserver = new MutationObserver
            (
                () =>
                {
                    JustifyTargetElements();
                }
            );
    
            ContentObserver.observe
            (
                document.body,
                {
                    childList: true,
                    subtree: true
                }
            );
        };
    
        // Run the script once the window is stable
        if (document.readyState === 'complete')
        {
            InitializeObserver();
        }
        else
        {
            window.addEventListener('load', InitializeObserver);
        }
    
    }
)();