tigt/web-syntaxes.md

## web-syntaxes.md

      
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              web-syntaxes.md
            
          
    Syntaxes

How many languages and syntaxes make up the Web?
This list is for code on the front-end; the back-end could be literally anything.
Notice this isn't about vocabularies. Many attributes have only certain values they accept, but syntaxes mean the characters are sorted/processed/handled a different way than usual.
The Big Ones

These are the macrolanguages that contain almost all of the other syntaxes.

URLs (Uniform Resource Locators)
HTTP (HyperText Transfer Protocol)
HTML (HyperText Markup Language)
XML (eXtensible Markup Language)
CSS (Cascading Style Sheets)
JavaScript (JavaScript)

Dialects

These descended from the macrolanguages and are (mostly) subsets of them.

HTML

HTML5 WAI-ARIA
HTML5 Serialization of SVG & MathML (Foreign Content Parsing)


XML

WAI-ARIA (Web Accessibility Initiative - Accessible Rich Internet Applications)
SVG (Scalable Vector Graphics)
SMIL
MathML (Math Markup Language)
TTML
RSS (Really Simple Syndication, among others)
Atom
XSL(T)
XPath
XLink
DASH
SSML (Speech Synthesis Markup Language)
OpenSearch Description
browserconfig.xml
Sitemaps Protocol


JavaScript

use strict;
JSON (JavaScript Object Notation)

JSON LD (Linked Data)
JWK (JSON Web Key)
Web App Manifests
Source maps


asm.js


WebAssembly
Data URIs

Miscellaneous Languages


WebVTT
AppCache
robots.txt
Plaintext sitemap
Session Description Protocol
GLSL (Graphics Library Shading Language; for WebGL)
WebAssembly
Event Stream (text/event-stream)

Anatomies of the Macrolanguages

URLs


Protocols/Schemes
Usernames & Passwords
Host

Domains & Subdomains
Punycode
IPv4 & IPv6
Port numbers


Path
Querystrings
Fragments

Fragment IDs
Media Fragments


Email Addresses
Relative URLs
URL-encoding

###HTTP###

Methods
Headers

Link Headers


HTTP Timestamps
Quality Lists
User-Agent Strings
HTTP Basic Authentication
Cookies
application/x-www-form-urlencoded
multipart/form-data
Content Security Policies
Certificates
Pragmas (Obsolete)

###HTML###

HTML tags & attributes
HTML character escapes
HTML comments
data- attributes
<meta name="viewport">
Microdata
Regular expressions (form accept attribute)
MIME types (type attribute)
<source-size-value>
srcset
Space-delimited lists (aria-, class)
Media queries (the media attribute)
coords
Vendor prefixes
ISO-6801 timestamps (datetime for the time, ins, and del elements)
target attribute values
classes
ids
Custom Elements
link[rel="icon"][sizes]
"DOCTYPEs" (HTML handles them differently)
RCDATA (<title> and <textarea>)
<script nonce>

###XML###

XML Tags & Attributes
XML comments
XML Character references
CDATA sections
DOCTYPE declarations
Processing instructions
DTDs
RelaxNG
W3C XML Schema
Schematron
NRL

###CSS###

Declarations
Selectors
Properties
calc()
CSS comments
CSS Character escapes
Media queries
Media conditions
Vendor prefixes
CSS variables
@-rules
:nth-child() & :nth-of-type()
Values/Units/Lengths/etc.
Gradient syntax
font-family names
Shorthand
Functions
CSS Shapes
Sourcemaps

###JavaScript###

JS comments
JS template strings
Regular expressions
Variables
Vendor prefixes
JS Character escapes
Array literals
Object literals
Strings
Numbers
Arguments
WebSQL
for
dataList handling
Operators
properties
keywords
properties/methods
Sourcemaps
booleans

###SVG###

<path d>
<polygon points>
viewBox
preserveAspectRatio

Colors

These are primarily used in CSS, but also have ancient HTML usage (bgcolor), new HTML usage (<meta name="theme-color">), and SVG usage (fill, stroke, other presentation attributes).

Hex codes
RGB(A)
HSL(A)
Early HTML color codes (bgcolor et al.; not syntactically different, but much weirder error-handling)
Named colors

Misc. Microsyntaxes


Language tags
Character sets
Numbers (positive, negative, floating-point)
base64
Whitespace
Fonts
CRL
MIME/Media Types
Regular expressions (JS, HTML's pattern attribute, CSS's @domain rule)

Dead Languages & Syntaxes

Once, they were of the Web. Now, they are no longer.

JSSS (JavaScript Style Sheets)
ViolaWWW stylesheets
ViolaWWW scripting
VBScript
P3P
Dart (kind of)
classids (& other <object> horrors)
IE filters (the progid: stuff)
Conditional comments (It wasn't just IE that supported them; <!--[if mso], "vector comments")
Conditional compilation
Pragmas
URL parameters (/parameter;value/)
VML (Vector Markup Language; IE5-8)
HTML+TIME (IE8)
QtScript
Cookies2 (defunct)
<plaintext> (Stopped all HTML parsing from that point on)
<xmp> (Didn't require escaping characters for example HTML code)
CSS Expressions
SGML (only kind of)
Anything related to Flash (like crossorigin.xml)