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A11y

Test for assessibility problems

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         A11y
// @namespace    assessibility.colivre.org
// @version      0.3
// @description  Test for assessibility problems
// @author       Aurélio A. Heckert
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Test if element has acessibility problems
    // If there is a problem, call `notify(el, <ERROR|WARN>, '<description string>')`
    function testA11yEl(el) {
        var id = el.id

        if (el.tagName == 'IMG' && emptyVal(el.alt) && emptyVal(el.title))
            notify(el, ERROR, 'Image without alt text.', 'https://www.w3.org/WAI/tutorials/images/');

        if (el.tagName == 'A' && noText(el))
            notify(el, ERROR, 'Link without text.');

        if (el.tagName == 'BUTTON' && noText(el))
            notify(el, ERROR, 'Button without text.');

        if (el.tagName.match(/^H[0-9]$/) && noText(el))
            notify(el, ERROR, `Heading ${el.tagName} without text.`);

        if (el.tagName.match(/^H[0-9]$/) && el.nextSibling &&
            el.nextSibling.tagName &&    // The next tag are united to this.
            el.nextSibling.tagName.match(/^H[0-9]$/))
            notify(el, WARN, `Skipping heading ${el.tagName}.`, 'https://www.w3.org/WAI/tutorials/page-structure/headings#heading-ranks');

        if (el.tagName.match(/^H[0-9]$/) && el.nextSibling && el.nextElementSibling &&
            el.nextSibling.constructor == Text && el.nextSibling.textContent.match(/^\s*$/) && // has no text between, only space.
            el.nextElementSibling.tagName.match(/^H[0-9]$/))
            notify(el, WARN, `Skipping heading ${el.tagName}.`, 'https://www.w3.org/WAI/tutorials/page-structure/headings#heading-ranks');

        if (el.tagName.match(/INPUT|TEXTAREA|SELECT/)    &&
             !(el.type=='submit' && !emptyVal(el.value)) &&
             !(el.type=='hidden')                        &&
             !(
               findAncestor(el, (a)=>a.tagName == 'LABEL') /* it is children of a <label> */ ||
               (id && document.querySelector(`label[for=${id}]`)) /* a <label> points to it */
             )
           )
            notify(el, ERROR, `Formfield ${el.tagName} without label.`, 'http://webaim.org/standards/508/checklist#standardn');

    }

    function noText(el) {
        var imgs = []
        imgs.push.apply(imgs, el.querySelectorAll('img'));
        return emptyVal(el) && emptyVal(el.title) && emptyVal(imgs.map((img)=> img.alt).join(''))
    }

    function findAncestor(el, matchFunc) {
        while (el = el.parentNode) {
            if (matchFunc(el)) return el;
        }
        return null;
    }

    var elements = [];
    var a11yBox, a11yList, pointer;
    const ERROR = 'ERROR';
    const WARN  = 'WARN';
    const BOXID = 'a11y-userscript-box';

    const $ = function(query) { return document.querySelector(query) };
    const $$ = function(query) { return document.querySelectorAll(query) };

    function emptyVal(val) {
        if (typeof(val) == 'string') val = val.replace(/\s/g, '');
        return typeof(val) == 'undefined' || val == null || val.length == 0
    }

    function mk(tag, attrs) {
        tag = document.createElement(tag);
        for (var attName in attrs) {
            var attVal = attrs[attName];
            if (attName == 'children') attVal.forEach(([t,a])=> {
                mk(t, Object.assign(a, {parent: tag}));
            });
            else if (attName == 'parent') attVal.appendChild(tag);
            else if (attName == 'text') tag.innerText = attVal;
            else if (attName == 'html') tag.innerHTML = attVal;
            else if (attName.match(/^on/)) tag[attName] = attVal;
            else tag.setAttribute(attName, attVal);
        }
        return tag;
    }

    function buildA11yBox() {
        a11yBox = mk('div', {
            parent: document.body,
            id: BOXID,
            class: BOXID+'-toggle-min',
            children: [
                ['i',{ id: BOXID+'-toggle-min-bt', onclick: toggleMin }]
            ]
        });
        a11yList = mk('ul', {parent: a11yBox});
        mk('style', {
            parent: document.documentElement.firstElementChild,
            html: `
                #${BOXID} {position: fixed; bottom: 0; right: 0; background: rgba(255,255,255,0.7); z-index: 99999; opacity: 1;
                    box-shadow: 0 0 30px rgba(0,0,0,0.6); padding: 15px; border-radius: 15px 0 0 0; color: #000}
                #${BOXID}-toggle-min-bt::before {content: "\\00d7"; position: absolute; top: 2px; left: 2px;
                    display: block; text-align: center; border: 1px solid #CCC; border-radius: 30px;
                    font-size: 24px; line-height: 24px; width: 24px; background: #EEE; cursor: pointer}
                #${BOXID} ul {margin: 0; padding: 0; border: 1px solid rgba(0,0,0,0.2);
                    border-top:none; max-height: 90vh; overflow: auto}
                #${BOXID} li {margin: 0; padding: 6px 10px; border-top: 1px solid rgba(0,0,0,0.1); list-style: none; cursor: pointer}
                .${BOXID}-toggle-min {opacity: 40%}
                .${BOXID}-toggle-min ul {display: none}
                .${BOXID}-ERROR {background: rgba(255,200,200,0.8)}
                .${BOXID}-WARN  {background: rgba(255,250,200,0.8)}
                #${BOXID} li span { font-size: 70%; padding-right: 1em }
                #${BOXID} li p { display: inline; margin: 0 }
                #${BOXID} li a { display: inline-block; margin: 0 0 0 3px; padding: 1px 2px; text-decoration: none;
                    border: 1px solid rgba(0,0,0,0.2); border-radius: 3px; color: #000 }
                #${BOXID}-pointer { position: absolute; left: -1000px; z-index: 99990;
                    border: 2px dashed #FFF; box-shadow: 0 0 110px 25px rgba(0,0,0,0.6) }
                #${BOXID}-pointer i { position: absolute; color: red; text-shadow: 1px 1px 1px #000, 0 0 8px #000;
                    font-size: 90px; line-height: 90px; text-align: center }
                #${BOXID}-pointer-N { top: -90px; width: 100% }
                #${BOXID}-pointer-S { bottom: -90px; width: 100% }
                #${BOXID}-pointer-W { left: -90px }
                #${BOXID}-pointer-E { right: -90px }
            `
        });
        pointer = mk('div', {
            parent: document.body,
            id: BOXID+'-pointer',
            children: [
                ['i', {id: BOXID+'-pointer-N', text: '↓'}],
                ['i', {id: BOXID+'-pointer-S', text: '↑'}],
                ['i', {id: BOXID+'-pointer-W', text: '→'}],
                ['i', {id: BOXID+'-pointer-E', text: '←'}]
            ]
        });
    }

    function toggleMin() {
        a11yBox.className = (a11yBox.className.length > 0)? '' : BOXID+'-toggle-min';
    }

    function notificationClick(notification, el) {
        var rect = el.getBoundingClientRect();
        var x = parseInt(rect.left + window.pageXOffset - 2);
        var y = parseInt(rect.top + window.pageYOffset - 2);
        var w = parseInt(rect.width + 4);
        var h = parseInt(rect.height + 4);
        pointer.style.left = x + 'px';
        pointer.style.top = y + 'px';
        pointer.style.width = w + 'px';
        pointer.style.height = h + 'px';
        $('#'+BOXID+'-pointer-W').style.lineHeight = h + 'px';
        $('#'+BOXID+'-pointer-E').style.lineHeight = h + 'px';
        window.scrollTo(parseInt(x-screen.width/4), parseInt(y-screen.height/4));
        console.log(el);
    }

    function notify(el, type, message, helpURL) {
        if (!a11yBox) buildA11yBox();
        if (elements.filter((reg)=> reg.el==el && reg.message==message).length > 0) return;
        elements.push({ el, message });
        var li = mk('li', {
            parent: a11yList,
            class: BOXID+'-'+type,
            onclick: ()=> notificationClick(this, el),
            children: [
                ['span', {text: type}],
                ['p', {text: message}],
            ]
        });
        if (helpURL) mk('a', {
            href: helpURL,
            target: '_blank',
            text: 'help',
            parent: li
        });
    }

    function walk(el) {
        if (el.id == BOXID) return;
        testA11yEl(el);
        for (var e,i=0; e=el.children[i]; i++) ((e)=> setTimeout(()=> walk(e), 1))(e);
    }

    function testPage() {
        console.log('testing page...');
        walk(document.body);
    }

    testPage();
    setInterval(testPage, 15000);
})();