This sample constructs an HTMLInfo that acts as a re-implementation of the default text editor.

The implementation is contained in the file TextEditor.js and exposes `window.TextEditor`, which is used in this file as the value of `myDiagram.toolManager.textEditingTool.defaultTextEditor`.

This also adds a text validation predicate, `okName`, as the TextBlock.textValidation property. That predicate makes sure that the new string has at least three characters and contains a vowel.

You can see additional custom text editors in the Custom TextEditingTool sample.

### GoJS Features in this sample

#### HTML Interaction

GoJS Diagrams can be used alongside other HTML elements in a webapp. For custom Text Editors, Context Menus, and ToolTips, which are invoked and hidden via GoJS tool operations, it is best to use the HTMLInfo class.

More information can be found in the GoJS Intro.

Related samples

#### GoJS Extensions

GoJS can be extended in a variety of ways. The most common way to change the standard behavior is to set properties on the GraphObject, Diagram, CommandHandler, Tool, or Layout. But when the desired property does not exist, you might need to override methods of CommandHandler, Tool, Layout, Link, or Node. Methods that you can override are documented in the API reference. Various features of GoJS can be overriden, either by replacing a method on an instance (a feature of JavaScript) or by defining a subclass. You should not modify the prototypes of any of the GoJS classes.

In addition to our samples, GoJS provides an extensions gallery, showcasing the creation of custom tools and layouts. Those classes and samples are written in TypeScript, available at `../extensionsJSM/`, as ECMAScript/JavaScript modules -- these use the `../release/go-module.js` library. We recommend that you copy the files that you need into your project, so that you can adjust how they refer to the GoJS library that you choose and so that you can include them into your own building and packaging procedures.

More information can be found in the GoJS Intro.

Related samples