# Default XML Schemas

> **TL;DR**
> `File | Settings | Languages & Frameworks | Schemas and DTDs | Default XML Schema` for Windows and Linux
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> `IntelliJ IDEA | Settings | Languages & Frameworks | Schemas and DTDs | Default XML Schema` for macOS
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> `Ctrl+Alt+S` (Windows), `⌘ Comma` (macOS), `⌘ Comma` (IntelliJ IDEA Classic (macOS)), `⌘ Comma` (macOS System Shortcuts), `Ctrl+Alt+S` (XWin), `Ctrl+Alt+S` (GNOME), `Ctrl+Alt+S` (KDE), `Ctrl+Alt+S` (Emacs), `Ctrl+Alt+S` (Sublime Text), `⌘ Comma` (Sublime Text (macOS)), `Ctrl+Alt+S` (NetBeans), `Ctrl+Alt+S` (Visual Studio), `⌘ Comma` (Visual Studio (macOS)), `Ctrl+Alt+S` (Eclipse), `⌘ Comma` (Eclipse (macOS)) ![the Settings icon](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app.expui.general.settings.svg)

## Default HTML Language Level

Normally, an HTML or an XHTML file has the `<!DOCTYPE>` declaration which states the language level of the used in the source code from the file. This language level is used as a standard against which the contents of the file are validated. If an HTML or an XHTML file does not have a `<!DOCTYPE>` declaration, the contents of the file will be validated against the default standard (schema).   In the Default HTML Language Level area, choose the default schema to validate HTML and XHTML files without a `<!DOCTYPE>` declaration.  The available options are:

* HTML 4 or HTML 5: select one of these options to have files treated as HTML 4 or HTML 5 and validated against one of these standards.

* Other doctype: select this option to have HTML files by default validated against a custom DTD or schema and specify the URL of the DTD or schema to be used. Note that code completion is available in this field: press `Ctrl+Space` (Windows), `⌃ Space` (macOS), `⌃ Space` (IntelliJ IDEA Classic (macOS)), `⌃ Space` (macOS System Shortcuts), `Ctrl+Space` (XWin), `Ctrl+Space` (GNOME), `Ctrl+Space` (KDE), `Alt+/` (Emacs), `Ctrl+Space` (Sublime Text), `⌃ Space` (Sublime Text (macOS)), `Ctrl+Space` (NetBeans), `Ctrl+Space` (Visual Studio), `⌃ Space` (Visual Studio (macOS)), `Ctrl+Space` (Eclipse), `⌃ Space` (Eclipse (macOS)) to see the list of suggested URLs. ![Default HTML language level dialog](https://resources.jetbrains.com.cn/help/img/idea/2026.2/defaultHtmlLangLevel.png)

## Default XML Schema Version

In this area,   choose the [XSD (XML Schema Definition) Schema](http://www.w3.org/XML/Schema) to validate XML files.  The available options are:

* XML Schema 1.1: for more information, refer to [W3C XML Schema Definition Language (XSD) 1.1 Part 1: Structures](http://www.w3.org/TR/xmlschema11-1/) and [W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes](http://www.w3.org/TR/xmlschema11-2/).

* XML Schema 1.0: for more information, refer to [XML Schema Part 1: Structures Second Edition](http://www.w3.org/TR/xmlschema-1/) and [XML Schema Part 2: Datatypes Second Edition](http://www.w3.org/TR/xmlschema-2/).

## See also

### Procedures

[Style Sheets](style-sheets.html)

[Validating web content files](validating-web-content-files.html)

### External Links

[Doc type declaration](http://en.wikipedia.org/wiki/Document_Type_Declaration)