Web Development Cheat Sheet
HTML Structure
Tag Name Description
<!DOCTYPE html> HTML !DOCTYPE Declaration All HTML documents must start with this tag and is information for the browser.
<html> HTML Tag Represents the root of an HTML document and contains all other HTML elements. Should include the lang="en" attribute.
<head> Head Tag Container for metadata that is placed between the <html> and <body> tag.
<meta> Meta Tag Defines meta data about an HTML document. The charset attribute specifies the character encoding of the HTML document. HTML5 encourages use of the UTF-8 character set.
<title> Title Tag Defines the title of the document and is displayed in the browser's toolbar.
<link> Link Tag Specifies relationships between the current document and an external resource. This could be a stylesheet, external fonts, etc.
<body> Body Tag Defines the document's body and contains all the contents of an HTML document.
HTML Boilerplate Sample
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible"
    content="IE=edge" />
    <meta name="viewport"
    content="width=device-width, 
    initial-scale=1.0" />
    <title>Document</title>
    <link rel="stylesheet" href="style.css" />
</head>
<body>

</body>
</html>
Semantic HTML
Tag Name Description
<header> Header Tag Represents a container for introductory content or a set of navigational links. You can have several <header> elements in one HTML document, however it should not be placed in a <footer>, <address> or another <header> element.
<nav> Nav Tag Defines a set of navigation links.
<article> Article Tag Specifies independent, self-contained content. An article should make sense on its own and it should be possible to distribute it independently from the site and still make sense.
<section> Section Tag Defines a section in a document.
<aside> Aside Tag Defines some content aside form the content it is placed in. The aside content should be indirectly related to the surrounding content.
<footer> Footer Tag Defines a footer for a document or section.Typically contains authorship information, copyright information, contact information, sitemap, back to top links, and/or related documents.
<figure> Figure Tag Specifies self-contained content, like illustrations, diagrams, photos, code class="table-html-tag" listings, etc.
<figcaption> Figcaption Tag Defines a caption for a <figure> element.
Semantic Layout Example
Semantic HTML layout diagram.
Semantic HTML layout diagram. Source
CSS Selectors

CSS Selectors refer to the HTML elements to which our CSS rules apply.

There are a variety of different types of selectors detailed in the table below: