It is based on Front-End developers' 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] means that the item is **recommended** but can be omitted in some particular situations.
* ![Medium][medium_img] means that the item is **highly recommended** and can eventually be omitted in some really particular cases. Some elements, if omitted, can have bad repercussions in terms of performance or SEO.
* ![High][high_img] means that the item **can't be omitted** by any reason. You may cause a dysfunction in your page or have accessibility or SEO issues. The testing priority needs to be on 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](https://github.com/thedaviddias/Front-End-Checklist/blob/master/CONTRIBUTING.md) which explains everything about the project.
---
## Head
> **Notes:** You can find [a list of everything](https://github.com/joshbuchea/HEAD) that could be found in the `` of an HTML document.
### Meta tag
* [ ] **Doctype:** ![High][high_img] The Doctype is HTML5 and is at the top of all your HTML pages.
```html
```
> * 📖 [Determining the character encoding - HTML5 W3C](https://www.w3.org/TR/html5/syntax.html#determining-the-character-encoding)
*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.
```html
```
* [ ] **Viewport:** ![High][high_img] The viewport is declared correctly.
```html
```
* [ ] **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).
```html
Page Title less than 55 characters
```
> * 📖 [Title - HTML - MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/title)
> * 🛠 [SERP Snippet Generator](https://www.sistrix.com/serp-snippet-generator/)
* [ ] **Description:** ![High][high_img] A meta description is provided, it is unique and doesn't possess more than 150 characters.
```html
```
> * 📖 [Meta Description - HTML - MDN](https://developer.mozilla.org/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML#Adding_an_author_and_description)
* [ ] **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).
```html
```
> * 🛠 [Favicon Generator](https://www.favicon-generator.org/)
> * 🛠 [RealFaviconGenerator](https://realfavicongenerator.net/)
> * 📖 [Favicon Cheat Sheet](https://github.com/audreyr/favicon-cheat-sheet)
> * 📖 [Favicons, Touch Icons, Tile Icons, etc. Which Do You Need? - CSS Tricks](https://css-tricks.com/favicon-quiz/)
> * 📖 [PNG favicons - caniuse](https://caniuse.com/#feat=link-icon-png)
* [ ] **Apple Web App Meta:** ![Low][low_img] Apple meta-tags are present.
```html
```
> * 📖 [Configuring Web Applications](https://developer.apple.com/library/content/documentation/AppleApplications/Reference/SafariWebContent/ConfiguringWebApplications/ConfiguringWebApplications.html)
> * 📖 [Supported Meta Tags](https://developer.apple.com/library/content/documentation/AppleApplications/Reference/SafariHTMLRef/Articles/MetaTags.html)
* [ ] **Windows Tiles:** ![Low][low_img] Windows tiles are present and linked.
```html
```
Minimum required xml markup for the `browserconfig.xml` file is as follows:
```xml
```
> * 📖 [Browser configuration schema reference](https://msdn.microsoft.com/en-us/library/dn320426(v=vs.85).aspx)
* [ ] **Canonical:** ![Medium][medium_img] Use `rel="canonical"` to avoid duplicate content.
```html
```
> * 📖 [Use canonical URLs - Search Console Help - Google Support](https://support.google.com/webmasters/answer/139066?hl=en)
> * 📖 [5 common mistakes with rel=canonical - Google Webmaster Blog](https://webmasters.googleblog.com/2013/04/5-common-mistakes-with-relcanonical.html)
### 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
```
* [ ] **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 - HTML - MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/dir)
* [ ] **Alternate language:** ![Low][low_img] The language tag of your website is specified and related to the language of the current page.
```html
```
* [ ] **x-default:** ![Low][low_img] The language tag of your website for international landing pages.
```html
```
> * 📖 [x-default - Google](https://webmasters.googleblog.com/2013/04/x-default-hreflang-for-international-pages.html)
* [ ] **Conditional comments:** ![Low][low_img] Conditional comments are present for IE if needed.
> * 📖 [About conditional comments (Internet Explorer) - MSDN - Microsoft](https://msdn.microsoft.com/en-us/library/ms537512(v=vs.85).aspx)
* [ ] **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 `` in a single line (minified).
> * 🛠 [Critical by Addy Osmani on GitHub](https://github.com/addyosmani/critical) automates this.
* [ ] **CSS order:** ![High][high_img] All CSS files are loaded before any JavaScript files in the ``. (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](https://metatags.io/)
***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.
```html
```
> * 📖 [A Guide to Sharing for Webmasters](https://developers.facebook.com/docs/sharing/webmasters/)
> * 📖 [Best Practices - Sharing](https://developers.facebook.com/docs/sharing/best-practices/)
> * 🛠 Test your page with the [Facebook OG testing](https://developers.facebook.com/tools/debug/)
* [ ] **Twitter Card:** ![Low][low_img]
```html
```
> * 📖 [Getting started with cards — Twitter Developers](https://developer.twitter.com/en/docs/tweets/optimize-with-cards/guides/getting-started)
> * 🛠 Test your page with the [Twitter card validator](https://cards-dev.twitter.com/validator)
**[⬆ back to top](#table-of-contents)**
---
## HTML
### Best practices
* [ ] **HTML5 Semantic Elements:** ![High][high_img] HTML5 Semantic Elements are used appropriately (header, section, footer, main...).
> * 📖 [HTML Reference](http://htmlreference.io/)
* [ ] **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](https://mathiasbynens.github.io/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](https://validator.w3.org/)
* [ ] **HTML Lint:** ![High][high_img] I use tools to help me analyze any issues I could have on my HTML code.
> * 🛠 [Dirty markup](https://www.10bestdesign.com/dirtymarkup/)
> * 🛠 [webhint](https://webhint.io/)
* [ ] **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](https://validator.w3.org/checklink)
* [ ] **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](https://andreicioara.com/use-adblocking-in-your-dev-environment-48db500d9b86)
**[⬆ back to top](#table-of-contents)**
---
## 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](https://developers.google.com/fonts/docs/technical_considerations)
* [ ] **Webfont format:** ![High][high_img] WOFF, WOFF2 and TTF are supported by all modern browsers.
> * 📖 [WOFF - Web Open Font Format - Caniuse](https://caniuse.com/#feat=woff).
> * 📖 [WOFF 2.0 - Web Open Font Format - Caniuse](https://caniuse.com/#feat=woff2).
> * 📖 [TTF/OTF - TrueType and OpenType font support](https://caniuse.com/#feat=ttf)
> * 📖 [Using @font-face - CSS-Tricks](https://css-tricks.com/snippets/css/using-font-face/)
* [ ] **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 loader
> * 🛠 [Typekit Web Font Loader](https://github.com/typekit/webfontloader)
**[⬆ back to top](#table-of-contents)**
---
## CSS
> **Notes:** Take a look at [CSS guidelines](https://cssguidelin.es/) and [Sass Guidelines](https://sass-guidelin.es/) followed by most Front-End developers. If you have a doubt about CSS properties, you can visit [CSS Reference](http://cssreference.io/). There is also a short [Code Guide](http://codeguide.co/) for consistency.
* [ ] **Responsive Web Design:** ![High][high_img] The website is using responsive web design.
* [ ] **CSS Print:** ![Medium][medium_img] A print stylesheet is provided and is correct on each page.
* [ ] **Preprocessors:** ![Low][low_img] Your project is using a CSS preprocessor (e.g [Sass](http://sass-lang.com/), [Less](http://lesscss.org/), [Stylus](http://stylus-lang.com/)).
* [ ] **Unique ID:** ![High][high_img] If IDs are used, they are unique to a page.
* [ ] **Reset CSS:** ![High][high_img] A CSS reset (reset, normalize or reboot) is used and up to date. *(If you are using a CSS Framework like Bootstrap or Foundation, a Normalize is already included into it.)*
> * 📖 [Reset.css](https://meyerweb.com/eric/tools/css/reset/)
> * 📖 [Normalize.css](https://necolas.github.io/normalize.css/)
> * 📖 [Reboot](https://getbootstrap.com/docs/4.0/content/reboot/)
* [ ] **JS prefix:** ![Low][low_img] All classes (or id- used in JavaScript files) begin with **js-** and are not styled into the CSS files.
```html
```
* [ ] **embedded or inline CSS:** ![High][high_img] Avoid at all cost embedding CSS in `
