Front-End-Checklist

<h1 align="center"> <br> <img src="https://raw.githubusercontent.com/thedaviddias/Front-End-Checklist/master/data/images/logo-front-end-checklist.jpg" alt="Front-End Checklist" width="130"> <br> <br> Front-End Checklist <br> </h1>

<h3 align="center">🚨 Currently working on new version of frontendchecklist.io,<br>feel free to <a href="https://github.com/thedaviddias/Front-End-Checklist/discussions/513">discuss</a> any feature you would like to see. Thanks for your support!</h3>

<h4 align="center">The Front-End Checklist is an exhaustive list of all elements you need to have / to test before launching your website / HTML page to production.</h4> <p align="center"> <a href="http://makeapullrequest.com"> <img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square" alt="PRs Welcome"> </a> <a href="https://github.com/thedaviddias/Front-End-Checklist/graphs/contributors"> <img src="https://img.shields.io/github/contributors/thedaviddias/Front-End-Checklist.svg?style=flat-square" alt="Contributors"> </a> <a href="https://github.com/thedaviddias/Front-End-Checklist/"> <img src="https://img.shields.io/badge/Front‑End_Checklist-followed-brightgreen.svg?style=flat-square" alt="Front‑End_Checklist followed"> </a> <a href="https://creativecommons.org/publicdomain/zero/1.0/"> <img src="https://img.shields.io/badge/license-CC0-green.svg?style=flat-square" alt="CC0"> </a> </p> <p align="center"> <a href="#how-to-use">How To Use</a> • <a href="#contributing">Contributing</a> • <a href="https://frontendchecklist.io">Website</a> • <a href="https://www.producthunt.com/posts/front-end-checklist">Product Hunt</a> </p> <p align="center"> <span>Other Checklists:</span> <br> <a href="https://github.com/thedaviddias/Front-End-Performance-Checklist#---------front-end-performance-checklist-">🎮 Front-End Performance Checklist</a> • <a href="https://github.com/thedaviddias/Front-End-Design-Checklist#front-end-design-checklist">💎 Front-End Design Checklist</a> </p>

It is based on Front-End developer's years of experience, with the additions coming from some other open-source checklists.

How to use?

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:

![Low][low_img] indicates that the item is recommended but can be omitted in certain situations. ![Medium][medium_img] indicates that the item is highly recommended but can potentially be omitted in very specific cases. However, omitting these elements can negatively impact performance or SEO. ![High][high_img] indicates that the item cannot be omitted under any circumstances. Removing these elements may result in page malfunctions or cause accessibility and SEO issues. Testing should prioritize these elements first.

Some resources possess an emoticon to help you understand which type of content / help you may find on the checklist:

📖: documentation or article
🛠: online tool / testing tool
📹: media or video content

You can contribute to the Front-End Checklist App reading the CONTRIBUTING.md file which explains everything about the project.

Head

Notes: You can find a list of everything that could be found in the <head> of an HTML document.

Meta tag

Doctype: ![High][high_img] The Doctype is HTML5 and is at the top of all your HTML pages.

<!doctype html> <!-- HTML5 -->

📖 Determining the character encoding - HTML5 W3C

The next 2 meta tags (Charset and Viewport) need to come first in the head.

Charset: ![High][high_img] The charset (UTF-8) is declared correctly.

<!-- Set character encoding for the document -->
<meta charset="utf-8">

Viewport: ![High][high_img] The viewport is declared correctly.

<!-- Viewport for responsive web design -->
<meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">

Title: ![High][high_img] A title is used on all pages (SEO: Google calculates the pixel width of the characters used in the title, and it cuts off between 472 and 482 pixels. The average character limit would be around 55-characters).

<!-- Document Title -->
<title>Page Title less than 55 characters</title>

📖 Title - HTML - MDN

🛠 SERP Snippet Generator

Description: ![High][high_img] A meta description is provided, it is unique and doesn't possess more than 150 characters.

<!-- Meta Description -->
<meta name="description" content="Description of the page less than 150 characters">

📖 Meta Description - HTML - MDN

Favicons: ![Medium][medium_img] Each favicon has been created and displays correctly. If you have only a 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 .ico format (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">
<!-- Recommended modern favicon format (not recommended for legacy browsers) -->
<link rel="icon" type="image/svg+xml" href="https://example.com/favicon.svg">

🛠 Favicon Generator

🛠 RealFaviconGenerator

📖 Favicon Cheat Sheet

📖 Favicons, Touch Icons, Tile Icons, etc. Which Do You Need? - CSS Tricks

📖 PNG favicons - caniuse

Apple Web App Meta: ![Low][low_img] Apple meta-tags are present.

<!-- 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">

📖 Configuring Web Applications

📖 Supported Meta Tags

Windows Tiles: ![Low][low_img] Windows tiles are present and linked.

<!-- 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>

📖 Browser configuration schema reference

Canonical: ![Medium][medium_img] Use 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">

📖 Use canonical URLs - Search Console Help - Google Support

📖 5 common mistakes with rel=canonical - Google Webmaster Blog

HTML tags

Language attribute: ![High][high_img] The lang attribute of your website is specified and related to the language of the current page.

<html lang="en">

Direction attribute: ![Medium][medium_img] The direction of lecture is specified on the html tag (It can be used on another HTML tag).

<html dir="rtl">

📖 dir - HTML - MDN

Alternate language: ![Low][low_img] The language tag of your website is specified and related to the language of the current page.

<link rel="alternate" href="https://es.example.com/" hreflang="es">

x-default: ![Low][low_img] The language tag of your website for international landing pages.

<link rel="alternate" href="https://example.com/" hreflang="x-default" />

📖 x-default - Google

Conditional comments: ![Low][low_img] Conditional comments are present for IE if needed.

📖 About conditional comments (Internet Explorer) - MSDN - Microsoft

RSS feed: ![Low][low_img] If your project is a blog or has articles, an RSS link was provided.
CSS Critical: ![Medium][medium_img] 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.

CSS order: ![High][high_img] All CSS files are loaded before any JavaScript files in the <head>. (Except the case where sometimes JS files are loaded asynchronously on top of your page).

Social meta

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.

Facebook Open Graph: ![Low][low_img] All Facebook Open Graph (OG) are tested and no one is missing or with false information. Images need to be at least 600 x 315 pixels, although 1200 x 630 pixels is recommended.

Notes: Using og:image:width and og:image:height will 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">

📖 A Guide to Sharing for Webmasters

📖 Best Practices - Sharing

🛠 Test your page with the Facebook OG testing

Twitter Card: ![Low][low_img]

<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">

📖 Getting started with cards — Twitter Developers

🛠 Test your page with the Twitter card validator

⬆ back to top

HTML

Best practices

HTML5 Semantic Elements: ![High][high_img] HTML5 Semantic Elements are used appropriately (header, section, footer, main...).

📖 HTML Reference

Error pages: ![High][high_img] 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: ![Medium][medium_img] 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 rel="noopener noreferrer".

📖 About rel=noopener

Clean up comments: ![Low][low_img] Unnecessary code needs to be removed before sending the page to production.

HTML testing

W3C compliant: ![High][high_img] All pages need to be tested with the W3C validator to identify possible issues in the HTML code.

🛠 W3C validator

HTML Lint: ![High][high_img] I use tools to help me analyze any issues I could have on my HTML code.

🛠 Dirty markup

🛠 webhint

Link checker: ![High][high_img] There are no broken links in my page, verify that you don't have any 404 error.

🛠 W3C Link Checker

Adblockers test: ![Medium][medium_img] Your website shows your content correctly with adblockers enabled (You can provide a message encouraging people to disable their adblocker).

📖 Use AdBlocking in your Dev Environment

⬆ back to top

Webfonts

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.

📖 Google Technical considerations about webfonts

Webfont format: ![High][high_img] WOFF, WOFF2 and TTF are supported by all modern browsers.

📖 WOFF - Web Open Font Format - Caniuse.

📖 WOFF 2.0 - Web Open Font Format - Caniuse.

📖 TTF/OTF - TrueType and OpenType font support

📖 Using @font-face - CSS-Tricks

Webfont size: ![High][high_img] Webfont sizes don't exceed 2 MB (all variants included).
Webfont loader: ![Low][low_img] Control loading behavior with a webfont