# Create a New Schema
This article describes how you can create a new [ProseMirror schema](https://www.telerik.com/blazor-ui/documentation/components/editor/prosemirror-schema/overview) for the Editor to use. Creating a new schema is useful if you want to change the majority of the default schema.
## Prerequisites
To work with ProseMirror, make sure you are familiar with:
* JavaScript—ProseMirror is a JavaScript library and the schema uses JavaScript syntax.
* ProseMirror Schema—The schema structure and its children (nodes and marks).
Modifying the ProseMirror Schema is outside of the Editor scope and we do not provide support for such customizations.
## Basics
The Editor accepts a custom ProseMirror schema through its `Schema` parameter. Set this `string` parameter to the name of a JavaScript function that:
* Is declared in the global scope (the `window` object).
* Returns an instance of the ProseMirror `Schema` class(the updated schema). You can access this class from the `ProseMirror` object of the event arguments.
* Accepts a single argument.
The Editor will call this function and will pass an argument object that contains the following properties:
| Property | Description |
| ------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `getSchema` | A function that returns the current `Schema` object. Before the Editor is initialized, the returned `Schema` object is the default schema of the Editor. After the Editor is initialized, the returned `Schema` object is the updated schema. If you don't provide a custom schema, this function always returns the default schema. |
| `getView` | A function that returns the currently used instance of the `EditorView` object. Before the Editor is initialized, the view (the result of the function) is null. |
| `ProseMirror` | An object that contains various ProseMirror classes and functions. |
> You can set a custom schema only once during initialization of the Editor component. Further changes to the schema will not take effect and the component will continue using the initial custom or built-in schema.
## Plugin Dependencies
Some of the ProseMirror plugins that the Editor uses by design depend on specific nodes in the default ProseMirror schema of the Editor. To get a collection of the default plugins, use the [`getPlugins` function](https://www.telerik.com/blazor-ui/documentation/components/editor/prosemirror-plugins#adding-a-custom-plugin).
When creating a new schema from scratch, it is possible to get an exception if you do not include the needed nodes in your custom schema.
You have several options in this case:
* Include the corresponding nodes in your custom schema.
* Get the collection of default plugins and remove the plugins that require the missing node.
* Pass a [custom empty collection of plugins to the Editor](https://www.telerik.com/blazor-ui/documentation/components/editor/prosemirror-plugins) to override the built-in ones.
Note that with the last two options you will lose the functionality that comes with the plugin(s) you remove.
## Creating a New Schema
The following example shows how to:
* Create a new instance of the `Schema` object and include several nodes and marks in it. The new schema supports only a couple of HTML elements such as ``, `