25 Additional Web Development Terms You May Not Have Heard Of

Published on February 1, 2022 (↻ February 25, 2024), filed under (RSS feed for all categories).

Web Development has its own, special vocabulary that easily consists of several thousand terms. No one knows all of them. Or do you? After sharing 33 terms here, 33 terms there, here are 25 more terms * you may or may not have heard of.

A proprietary, unofficial CSS unit (“quirky em”) to manage margins in reflow roots (body, th, and td) similar to the Internet Explorer web browser. According to the source code, “When the quirky value is used, if you’re in quirks mode, the margin will collapse away inside a table cell.” __qem was originally spelled with one underscore, _qem.
An early commercial web browser based on the NCSA Mosaic browser. AirMosaic was released in 1994.
BGP (Border Gateway Protocol)
A standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems on the Internet. BGP is classified as a path-vector routing protocol, and it makes routing decisions based on paths, network policies, or rule sets configured by a network administrator. It was first described in 1989 in RFC 1105, and has been in use on the Internet since 1994.
Channel messaging
An API described by the HTML specification that enables independent pieces of code (e.g., scripts in different browsing contexts) to communicate directly. Channel messaging works through two-way channels (or pipes) with a port at each end.
Content category
A category that HTML puts elements in. The main categories are metadata content, flow content, sectioning content, heading content, phrasing content, embedded content, and interactive content. [Learn more in my article on HTML content categories.]
Cyclomatic complexity
A software metric used to indicate the complexity of a program. It is a quantitative measure of the number of linearly independent paths through a program’s source code, and is computed using the control-flow graph of the program. The nodes of the graph correspond to indivisible groups of commands of a program, and a directed edge connects two nodes if the second command might be executed immediately after the first command. Cyclomatic complexity may also be applied to individual functions, modules, methods, or classes. It was developed in 1976 by Thomas J. McCabe, Sr.
DOM clobbering
The injection of HTML into a web page with the goal of manipulating the DOM and escalating the injection to a cross-site scripting (XSS) attack. For example, one form of DOM clobbering uses an a element to overwrite a global variable for malicious purposes.
Flame graph
A flame-like visualization method for software profiling. is.gd/EnyPjs
GRASP (General Responsibility Assignment Software Patterns)
Guidelines for assigning responsibility to classes and objects in object-oriented design. The different patterns and principles used in GRASP are controller, creator, indirection, information expert, low coupling, high cohesion, polymorphism, protected variations, and pure fabrication.
Homogenous migration
A migration where source and target systems are of the same type.
Islands architecture
The use of placeholders for dynamic parts of a web page, to be loaded and hydrated separately in order to improve perceived performance.
JSON5 (JSON5 Data Interchange Format)
An unofficial superset of, and proposed extension to, the JSON format. The goal of JSON5 is to make it easier for people to write and maintain JSON. Its features relate to the handling of objects, arrays, strings, numbers, and comments. JSON5 is suggested to have a special file extension, .json5, as well as a different MIME type. json5.org
A web browser for Microsoft Windows based on the Gecko layout engine. K-Meleon was first released in 2000. kmeleonbrowser.org
A web design approach in which page elements have a variable as opposed to a fixed width. Liquid design is a predecessor for responsive design.
Neutral character
A character that has direction indeterminable without context. Examples include paragraph separators, tabs, and most other whitespace characters. Punctuation symbols that are common to many scripts, such as the colon, comma, full stop, and the no-break space also fall within this category.
NUI (Natural user interface)
A user interface that is effectively invisible, and remains invisible as the user learns increasingly complex interactions. The word “natural“ is used because most computer interfaces use artificial control devices whose operation has to be learned. Examples include voice assistants, such as Alexa and Siri, touch and multi-touch interactions on today’s mobile phones and tablets, but also touch interfaces invisiblly integrated into the textiles furnitures.
OOPIF (Out-of-Process Iframe)
An iframe that’s being handled in a different rendering process for security reasons.
PCDATA (Parsed Character Data)
A data definition that originated in Standard Generalized Markup Language (SGML), and that is also used in Extensible Markup Language (XML) document type definitions to designate mixed content XML elements.
Reactive Manifesto
A systems architecture approach in which it is declared necessary for systems to be responsive, resilient, elastic, and message-driven. Such systems are considered reactive systems. reactivemanifesto.org
Squint test
An improvised test for the effectiveness of a design, involving to squint the eyes when looking at the design to assess visual structure and hierarchy.
The inclusion of part or all of an electronic document into one or more other documents by hypertext reference. Transclusion is usually performed when the referencing document is displayed, and is normally automatic and transparent to the end user. The result of transclusion is a single integrated document made of parts assembled dynamically from separate sources, possibly stored on different computers in disparate places.
UXSS (Universal Cross-Site Scripting)
An attack that exploits vulnerabilities in a browser or browser extension (instead of a website or application, as with XSS) in order to run malicious code.
WebVTT (Web Video Text Tracks)
A World Wide Web Consortium (W3C) standard for displaying timed text in connection with the HTML track element. The early drafts of the specification were written by the WHATWG in 2010 after discussions about what caption format should be supported by HTML. w3.org/TR/webvtt1
An augmentation of PHP and Hack developed at Facebook to allow XML syntax for the purpose of creating custom and reusable HTML elements. XHP was first released in 2010.
Zero-based indexing
A way of numbering in which the initial element of a sequence is assigned the index 0, rather than the index 1 as is typical in everyday non-mathematical or non-programming circumstances. Under zero-indexed or zero-based numbering, the initial element is sometimes termed the “zeroth” element, rather than the first element; “zeroth” is a coined ordinal number corresponding to the number zero.

The cover of “The Web Development Glossary.”

How many terms did you know? How many terms had you heard about? What was new?

Web Development is a great field. If you decide to follow the field’s development through the The Web Development Glossary, you get book updates automatically when obtaining your copy at Google Play Books or Leanpub (other vendors). Have a look!

* Some explanations are based on Wikipedia, the MDN Web Docs, or the HTML Living Standard. All references are available in the Appendix of The Web Development Glossary (PDF). This post is licensed under a CC BY-SA 4.0 (Attribution-ShareAlike 4.0 International) license.

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About Me

Jens Oliver Meiert, on September 30, 2021.

I’m Jens (long: Jens Oliver Meiert), and I’m a frontend engineering leader and tech author/publisher. I’ve worked as a technical lead for companies like Google and as an engineering manager for companies like Miro, I’m close to W3C and WHATWG, and I write and review books for O’Reilly and Frontend Dogma.

I love trying things, not only in web development (and engineering management), but also in other areas like philosophy. Here on meiert.com I share some of my views and experiences.

If you want to do me a favor, interpret charitably (I speak three languages, and they can collide), yet be critical and give feedback for me to learn and improve. Thank you!