Bunpro: Disable Backspace Undo

Disables the backspace functionality in reviews

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         Bunpro: Disable Backspace Undo
// @namespace    http://tampermonkey.net/
// @version      1.0.6
// @description  Disables the backspace functionality in reviews
// @author       Kumirei
// @include      *bunpro.jp/*
// @exclude      *community.bunpro.jp*
// @require      https://greasyfork.org/scripts/370623-bunpro-helpful-events/code/Bunpro:%20Helpful%20Events.js?version=974369
// @grant        none
// ==/UserScript==

(function() {
    var $ = window.$;
    $('html')[0].addEventListener('quiz-page', ()=>{
        var input_elem = $('#study-answer-input');
        $('body').keydown((event)=>{
            var colors = input_elem.css('background-color').match(/\d+/g);
            var sum = colors.reduce((a, b)=>Number(a)+Number(b));
            var redness = colors[0]/sum;
            if (event.keyCode == 8 && redness > 0.4) {
                event.stopPropagation();
                input_elem.blur();
            }
        });
    });
})();