HTML - Rich Text Editor (Edition)


A rich text editor is a component that permits to edit text to make it rich. ie it allows the text to be styled via editing button.

Basic Example

This code is explained in the html editor section. If you want to see the code, hover over the form and click on the Try this code button.

Ref: Example adapted from the Editing section of the spec

How it works

HTML Editor

Editable element

The most simple implementation are made via Javascript that manipulates directly the syntax tree of the HTML document called the DOM.

The content is made editable with the contentEditable attribute and the user edit that text.

In other words, the HTML DOM is edited. ie when the user bolds a word, a b html element is added.

The styling buttons are implemented with:

  • the execCommand This function will be replaced by Content Editable and Input Events but they are still not fully implemented

The basic example is using the execCommand.


If you need to create text that is constrained in a fix format such as a page A4, you may want to use a canvas instead. 1). Google docs use it with their Kix editor 2)

Other Language Editor

If you want to create a editor for another language, there is two possible architectures that increase in complexity:

  • an unidirectional editor, the easiest, where you translate your language to HTML
  • or a bidirectional editor, the hardest, where you need also to translate the HTML back to your language.


To translate you language to HTML, you can do it:

  • with a function directly (one pass)
  • or via a parser that builds a syntax tree

Example of parser:

Virtual DOM

The HTML dom may be and is generally virtual. Editor may use:

Some implements also their own such as:

The advantage of a virtual DOM is that the page does not need to be entirely refreshed. The virtual dom is making the diff and its update transparent.

Keep in mind that the DOM implementation chosen will limit the expressiveness of your language.

It's easy to add a inline feature such as bold but it's:

  • less easy to define hierarchical component such as :
    • a table,
    • or a image gallery
  • even less if you want to introduce templating feature such as:
    • the list of the last 10 pages published


To smoothing the experience and to not render on every stroke, you should apply a debounce. It reduces overhead by not rendering for every keystroke. The rendering is triggered via a keystroke or a timer.

Sanitization / Security

To avoid Xss attack, your input should be sanitized to delete every scriptable/callable text also on the server please as the client code is never reliable.


This sections regroups:

  • the rich text editor
  • but also the code editor because if you are creating a markup language, you may also just want to go this route.

Rich Text Editor

Gutenberg Wordpress


react-contenteditable - Example with:

  • two directions update between HTML Text to React HTML Dom
  • with a edit button powered by execCommand to modify the HTML


Draft.js - Framework for building rich text editors in React such as:


(Used by purpose)

Prosemirror uses its own sort of DOM with one important difference, is that it stops to be recursive in inline/paragraph node 3)

Prose Mirror Paragraph Dom Xml Paragraph Dom

The explanation is that it :

  • allows to represent positions in a paragraph using a character offset rather than a path in a tree,
  • makes it easier to perform operations like splitting or changing the style of the content without performing tree manipulation.


Squire - Largely used. The HTML remains the source-of-truth (the DOM)

Syntax tree to HTML

Medium Editor

Medium Editor - Simple project, buggy in the extension that shows a medium like editor



Text editor based on canvas.

Code Editor

If you are creating a markup language, you may also just want to implement the modification in a code editor such as

See also

Language Server Protocol

  • Language Server Protocol - Interface protocol used between an editor or IDE and a language server that provides language features like auto complete, go to definition, find all references etc.

Template Editor / Page Builder

WYSIWYG editors are good for content editing but inappropriate for creating HTML structures.

Documentation / Reference

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