Zawsze staraj się o egzekwowanie tych, lub własnych, uzgodnionych wytycznych. Małe czy duże, nazywaj po imieniu to co jest błędne. Po uzupełnienia lub wkłady własne do tego Przewodnika, proszę otworzyć problem na GitHub.
Każda linia kodu powinna wyglądać ja napisana przez jedną osobę, bez względu na liczbę uczestników.
</li> or </body>).<!DOCTYPE html>
<html>
<head>
<title>Page title</title>
</head>
<body>
<img src="images/company-logo.png" alt="Company">
<h1 class="hello-world">Hello, world!</h1>
</body>
</html>Użycie deklaracji doctype na początku każdej strony HTML wymusza tryb standardu oraz bardziej spójne wyswietlanie zawartości w każdej przeglądarce (gdzie jest to możliwe).
<!DOCTYPE html>
<html>
<head>
</head>
</html>From the HTML5 spec:
Autorzy są zachęcani, aby określić atrybut jezyka na elemencie głównym dokumentcie HTML. Dzięki temu ułatwiamy pracę narzędziom syntezy mowy, narzędzi tłumaczeniowych, i tak dalej...
Read more about the lang attribute in the spec.
Head to Sitepoint for a list of language codes.
<html lang="en-us">
<!-- ... -->
</html>Internet Explorer supports the use of a document compatibility <meta> tag to specify what version of IE the page should be rendered as. Unless circumstances require otherwise, it's most useful to instruct IE to use the latest supported mode with edge mode.
For more information, read this awesome Stack Overflow article.
<meta http-equiv="X-UA-Compatible" content="IE=Edge">Quickly and easily ensure proper rendering of your content by declaring an explicit character encoding. When doing so, you may avoid using character entities in your HTML, provided their encoding matches that of the document (generally UTF-8).
<head>
<meta charset="UTF-8">
</head>Per HTML5 spec, typically there is no need to specify a type when including CSS and JavaScript files as text/css and text/javascript are their respective defaults.
<!-- External CSS -->
<link rel="stylesheet" href="code-guide.css">
<!-- In-document CSS -->
<style>
/* ... */
</style>
<!-- JavaScript -->
<script src="code-guide.js"></script>Strive to maintain HTML standards and semantics, but not at the expense of practicality. Use the least amount of markup with the fewest intricacies whenever possible.
HTML attributes should come in this particular order for easier reading of code.
classid, namedata-*src, for, type, href, valuetitle, altaria-*, roleClasses make for great reusable components, so they come first. Ids are more specific and should be used sparingly (e.g., for in-page bookmarks), so they come second.
<a class="..." id="..." data-modal="toggle" href="#">
Example link
</a>
<input class="form-control" type="text">
<img src="..." alt="...">A boolean attribute is one that needs no declared value. XHTML required you to declare a value, but HTML5 has no such requirement.
For further reading, consult the WhatWG section on boolean attributes:
The presence of a boolean attribute on an element represents the true value, and the absence of the attribute represents the false value.
If you must include the attribute's value, and you don't need to, follow this WhatWG guideline:
If the attribute is present, its value must either be the empty string or [...] the attribute's canonical name, with no leading or trailing whitespace.
In short, don't add a value.
<input type="text" disabled>
<input type="checkbox" value="1" checked>
<select>
<option value="1" selected>1</option>
</select>Whenever possible, avoid superfluous parent elements when writing HTML. Many times this requires iteration and refactoring, but produces less HTML. Take the following example:
<!-- Not so great -->
<span class="avatar">
<img src="...">
</span>
<!-- Better -->
<img class="avatar" src="...">Writing markup in a JavaScript file makes the content harder to find, harder to edit, and less performant. Avoid it whenever possible.
: for each declaration.box-shadow).rgb(), rgba(), hsl(), hsla(), or rect() values. This helps differentiate multiple color values (comma, no space) from multiple property values (comma with space)..5 instead of 0.5 and -.5px instead of -0.5px).#fff. Lowercase letters are much easier to discern when scanning a document as they tend to have more unique shapes.#fff instead of #ffffff.input[type="text"]. They’re only optional in some cases, and it’s a good practice for consistency.margin: 0; instead of margin: 0px;.Questions on the terms used here? See the syntax section of the Cascading Style Sheets article on Wikipedia.
/* Bad CSS */
.selector, .selector-secondary, .selector[type=text] {
padding:15px;
margin:0px 0px 15px;
background-color:rgba(0, 0, 0, 0.5);
box-shadow:0px 1px 2px #CCC,inset 0 1px 0 #FFFFFF
}
/* Good CSS */
.selector,
.selector-secondary,
.selector[type="text"] {
padding: 15px;
margin-bottom: 15px;
background-color: rgba(0,0,0,.5);
box-shadow: 0 1px 2px #ccc, inset 0 1px 0 #fff;
}Related property declarations should be grouped together following the order:
Positioning comes first because it can remove an element from the normal flow of the document and override box model related styles. The box model comes next as it dictates a component's dimensions and placement.
Everything else takes place inside the component or without impacting the previous two sections, and thus they come last.
For a complete list of properties and their order, please see Recess.
.declaration-order {
/* Positioning */
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
z-index: 100;
/* Box-model */
display: block;
float: right;
width: 100px;
height: 100px;
/* Typography */
font: normal 13px "Helvetica Neue", sans-serif;
line-height: 1.5;
color: #333;
text-align: center;
/* Visual */
background-color: #f5f5f5;
border: 1px solid #e5e5e5;
border-radius: 3px;
/* Misc */
opacity: 1;
}@importCompared to <link>s, @import is slower, adds extra page requests, and can cause other unforeseen problems. Avoid them and instead opt for an alternate approach:
<link> elementsFor more information, read this article by Steve Souders.
<!-- Use link elements -->
<link rel="stylesheet" href="core.css">
<!-- Avoid @imports -->
<style>
@import url("more.css");
</style>Place media queries as close to their relevant rule sets whenever possible. Don't bundle them all in a separate stylesheet or at the end of the document. Doing so only makes it easier for folks to miss them in the future. Here's a typical setup.
.element { ... }
.element-avatar { ... }
.element-selected { ... }
@media (min-width: 480px) {
.element { ...}
.element-avatar { ... }
.element-selected { ... }
}When using vendor prefixed properties, indent each property such that the declaration's value lines up vertically for easy multi-line editing.
In Textmate, use Text → Edit Each Line in Selection (⌃⌘A). In Sublime Text 2, use Selection → Add Previous Line (⌃⇧↑) and Selection → Add Next Line (⌃⇧↓).
/* Prefixed properties */
.selector {
-webkit-box-shadow: 0 1px 2px rgba(0,0,0,.15);
box-shadow: 0 1px 2px rgba(0,0,0,.15);
}In instances where a rule set includes only one declaration, consider removing line breaks for readability and faster editing. Any rule set with multiple declarations should be split to separate lines.
The key factor here is error detection—e.g., a CSS validator stating you have a syntax error on Line 183. With a single declaration, there's no missing it. With multiple declarations, separate lines is a must for your sanity.
/* Single declarations on one line */
.span1 { width: 60px; }
.span2 { width: 140px; }
.span3 { width: 220px; }
/* Multiple declarations, one per line */
.sprite {
display: inline-block;
width: 16px;
height: 15px;
background-image: url(../img/sprite.png);
}
.icon { background-position: 0 0; }
.icon-home { background-position: 0 -20px; }
.icon-account { background-position: 0 -40px; }Strive to limit use of shorthand declarations to instances where you must explicitly set all the available values. Common overused shorthand properties include:
paddingmarginfontbackgroundborderborder-radiusOften times we don't need to set all the values a shorthand property represents. For example, HTML headings only set top and bottom margin, so when necessary, only override those two values. Excessive use of shorthand properties often leads to sloppier code with unnecessary overrides and unintended side effects.
The Mozilla Developer Network has a great article on shorthand properties for those unfamiliar with notation and behavior.
/* Bad example */
.element {
margin: 0 0 10px;
background: red;
background: url("image.jpg");
border-radius: 3px 3px 0 0;
}
/* Good example */
.element {
margin-bottom: 10px;
background-color: red;
background-image: url("image.jpg");
border-top-left-radius: 3px;
border-top-right-radius: 3px;
}Avoid unnecessary nesting. Just because you can nest, doesn't mean you always should. Consider nesting only if you must scope styles to a parent and if there are multiple elements to be nested.
// Without nesting
.table > thead > tr > th { … }
.table > thead > tr > td { … }
// With nesting
.table > thead > tr {
> th { … }
> td { … }
}Code is written and maintained by people. Ensure your code is descriptive, well commented, and approachable by others. Great code comments convey context or purpose. Do not simply reiterate a component or class name.
Be sure to write in complete sentences for larger comments and succinct phrases for general notes.
/* Bad example */
/* Modal header */
.modal-header {
...
}
/* Good example */
/* Wrapping element for .modal-title and .modal-close */
.modal-header {
...
}.btn and .btn-danger)..btn is useful for button, but .s doesn't mean anything..js-* classes to denote behavior (as opposed to style), but keep these classes out of your CSS.It's also useful to apply many of these same rules when creating Sass and Less variable names.
/* Bad example */
.t { ... }
.red { ... }
.header { ... }
/* Good example */
.tweet { ... }
.important { ... }
.tweet-header { ... }[class^="..."]) on commonly occuring components. Browser performance is known to be impacted by these.Additional reading:
/* Bad example */
span { ... }
.page-container #stream .stream-item .tweet .tweet-header .username { ... }
.avatar { ... }
/* Good example */
.avatar { ... }
.tweet-header .username { ... }
.tweet .avatar { ... }/*
* Component section heading
*/
.element { ... }
/*
* Component section heading
*
* Sometimes you need to include optional context for the entire component. Do that up here if it's important enough.
*/
.element { ... }
/* Contextual sub-component or modifer */
.element-heading { ... }Set your editor to the following settings to avoid common code inconsistencies and dirty diffs:
Consider documenting and applying these preferences to your project's .editorconfig file. For an example, see the one in Bootstrap. Learn more about EditorConfig.