It is based on Front-End developers' years of experience, with the additions coming from some other open-source checklists.
All items in the Front-End Checklist are required for the majority of the projects, but some elements can be omitted or are not essential (in the case of an administration web app, you may not need RSS feed for example). We choose to use 3 levels of flexibility:
Some resources possess an emoticon to help you understand which type of content / help you may find on the checklist:
You can contribute to the Front-End Checklist App reading the CONTRIBUTING.md file which explains everything about the project.
Notes: You can find a list of everything that could be found in the
<head>of an HTML document.
<!doctype html> <!-- HTML5 -->
The next 2 meta tags (Charset and Viewport) need to come first in the head.
<!-- Set character encoding for the document --> <meta charset="utf-8">
<!-- Viewport for responsive web design --> <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
<!-- Document Title --> <title>Page Title less than 55 characters</title>
<!-- Meta Description --> <meta name="description" content="Description of the page less than 150 characters">
favicon.ico, put it at the root of your site. Normally you won't need to use any markup. However, it's still good practice to link to it using the example below. Today, PNG format is recommended over
.icoformat (dimensions: 32x32px).
<!-- Standard favicon --> <link rel="icon" type="image/x-icon" href="https://example.com/favicon.ico"> <!-- Recommended favicon format --> <link rel="icon" type="image/png" href="https://example.com/favicon.png">
<!-- Apple Touch Icon (at least 200x200px) --> <link rel="apple-touch-icon" href="/custom-icon.png"> <!-- To run the web application in full-screen --> <meta name="apple-mobile-web-app-capable" content="yes"> <!-- Status Bar Style (see Supported Meta Tags below for available values) --> <!-- Has no effect unless you have the previous meta tag --> <meta name="apple-mobile-web-app-status-bar-style" content="black">
<!-- Microsoft Tiles --> <meta name="msapplication-config" content="browserconfig.xml" />
Minimum required xml markup for the
browserconfig.xml file is as follows:
<?xml version="1.0" encoding="utf-8"?> <browserconfig> <msapplication> <tile> <square70x70logo src="small.png"/> <square150x150logo src="medium.png"/> <wide310x150logo src="wide.png"/> <square310x310logo src="large.png"/> </tile> </msapplication> </browserconfig>
rel="canonical"to avoid duplicate content.
<!-- Helps prevent duplicate content issues --> <link rel="canonical" href="http://example.com/2017/09/a-new-article-to-read.html">
langattribute of your website is specified and related to the language of the current page.
<link rel="alternate" href="https://es.example.com/" hreflang="es">
<link rel="alternate" href="https://example.com/" hreflang="x-default" />
[ ] RSS feed: If your project is a blog or has articles, an RSS link was provided.
[ ] CSS Critical: The CSS critical (or "above the fold") collects all the CSS used to render the visible portion of the page. It is embedded before your principal CSS call and between
<style></style> in a single line (minified).
- 🛠 Critical by Addy Osmani on GitHub automates this.
<head>. (Except the case where sometimes JS files are loaded asynchronously on top of your page).
Visualize and generate automatically our social meta tags with Meta Tags
Facebook OG and Twitter Cards are, for any website, highly recommended. The other social media tags can be considered if you target a particular presence on those and want to ensure the display.
og:image:heightwill specify the image dimensions to the crawler so that it can render the image immediately without having to asynchronously download and process it.
<meta property="og:type" content="website"> <meta property="og:url" content="https://example.com/page.html"> <meta property="og:title" content="Content Title"> <meta property="og:image" content="https://example.com/image.jpg"> <meta property="og:description" content="Description Here"> <meta property="og:site_name" content="Site Name"> <meta property="og:locale" content="en_US"> <!-- Next tags are optional but recommended --> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="630">
<meta name="twitter:card" content="summary"> <meta name="twitter:site" content="@site_account"> <meta name="twitter:creator" content="@individual_account"> <meta name="twitter:url" content="https://example.com/page.html"> <meta name="twitter:title" content="Content Title"> <meta name="twitter:description" content="Content description less than 200 characters"> <meta name="twitter:image" content="https://example.com/image.jpg">
[ ] Error pages: Error 404 page and 5xx exist. Remember that the 5xx error pages need to have their CSS integrated (no external call on the current server).
[ ] Noopener: In case you are using external links with
target="_blank", your link should have a
rel="noopener" attribute to prevent tab nabbing. If you need to support older versions of Firefox, use
- 🛠 webhint
Notes: Using web fonts may cause Flash Of Unstyled Text/Flash Of Invisible Text - consider having fallback fonts and/or utilizing web font loaders to control behavior.
[ ] Webfont size: Webfont sizes don't exceed 2 MB (all variants included).
[ ] Webfont loader: Control loading behavior with a webfont loader
Notes: Take a look at CSS guidelines and Sass Guidelines followed by most Front-End developers. If you have a doubt about CSS properties, you can visit CSS Reference. There is also a short Code Guide for consistency.
<div id="js-slider" class="my-slider"> <!-- Or --> <div id="id-used-by-cms" class="js-slider my-slider">
<style>tags or using inline CSS: only use for valid reasons (e.g. background-image for slider, critical CSS).
[ ] Desktop Browsers: All pages were tested on all current desktop browsers (Safari, Firefox, Chrome, Internet Explorer, EDGE...).
[ ] Mobile Browsers: All pages were tested on all current mobile browsers (Native browser, Chrome, Safari...).
[ ] OS: All pages were tested on all current OS (Windows, Android, iOS, Mac...).
[ ] Design fidelity: Depending on the project and the quality of the creatives, you may be asked to be close to the design. You can use some tools to compare creatives with your code implementation and ensure consistency.
Notes: For a complete understanding of image optimization, check the free ebook Essential Image Optimization from Addy Osmani.
- 🛠 Imagemin
- 🛠 Use ImageOptim to optimise your images for free.
- 🛠 Use KeyCDN Image Processing for image optimization in real time.
- 🛠 Use Kraken.io awesome alternative for both png and jpg optimization. Up to 1mb per files on free plan.
- 🛠 TinyPNG optimises png, apng (animated png) and jpg images with very small loss in quality. Free and paid version available.
- 🛠 ZorroSVG jpg-like compression for transparent images using svg masking.
- 🛠 SVGO a Nodejs-based tool for optimizing SVG vector graphics files.
- 🛠 SVGOMG a web-based GUI version of SVGO for optimising your svgs online.
<img>if the final rendered image size is known (can be omitted for CSS sizing).
<img>have an alternative text which describes the image visually.
<noscript>tag in the HTML body if a script type on the page is unsupported or if scripting is currently turned off in the browser. This will be helpful in client-side rendering heavy apps such as React.js, see examples.
asyncor deferred using
[ ] Minified HTML: Your HTML is minified.
[ ] Lazy loading: Images, scripts and CSS need to be lazy loaded to improve the response time of the current page (See details in their respective sections).
[ ] Cookie size: If you are using cookies be sure each cookie doesn't exceed 4096 bytes and your domain name doesn't have more than 20 cookies.
<link rel="dns-prefetch" href="https://example.com">
<link rel="preconnect" href="https://example.com">
<link rel="prefetch" href="image.png">
<body>) in advance using
<link rel="preload" href="app.js">
Notes: You can watch the playlist A11ycasts with Rob Dodson 📹
- 📖 Introduction to Structured Data - Search - Google Developers
- 📖 JSON-LD
- 📖 Microdata
- 🛠 Test your page with the Rich Results Test
- 🛠 Complete list of vocabularies that can be used as structured data. Schema.org Full Hierarchy
The Front-End Checklist is also available in other languages. Thanks for all translators and their awesome work!
If you want to show you are following the rules of the Front-End Checklist, put this badge on your README file!
Open an issue or a pull request to suggest changes or additions.
The Front-End Checklist repository consists of two branches:
This branch consists of the
README.md file that is automatically reflected on the Front-End Checklist website.
This branch will be used to make some significant changes to the structure, content if needed. It is preferable to use the master branch to fix small errors or add a new item.
If you have any question or suggestion, don't hesitate to use Gitter or Twitter:
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