# "js" Tag Configure the **"js"** tag in the [config.json](https://developer.harmonyos.com/en/docs/documentation/doc-guides/basic-config-file-overview-0000000000011951) file of your application. The **"js"** tag contains the instance name, page route, and window configuration information.

Tag

Type

Default Value

Mandatory

Description

name

string

default

Yes

Name of the eTS instance.

pages

Array

-

Yes

Page route information. For details, see "pages".

window

Object

-

No

Window configuration information. For details, see "window".

mode

Object

-

No

Running type and syntax style of the JS component. For details, see "mode".
## pages The **"pages"** defines the route information of each page's entry component. Each page consists of the page path and page name. The following is an example: ``` { "pages": [ "pages/index", "pages/detail" ] } ``` >![](../public_sys-resources/icon-note.gif) **NOTE:** >- The first page in the **"pages"** list is the home page of the application. >- The page name must not be a component name, for example, **Text.ets** or **Button.ets**. >- Each page file must contain the [page entry component](ts-component-based-entry.md) \(with the @Entry decoration\). ## window The **"window"** configures the view window. The following attributes can be configured:

Type

Default Value

Description

designWidth

-

Logical width of the view. The default value is 720. (The default value is 454 for wearables.) The logical width of the view determines the unit size of lpx. For example, if designWidth is 720 and the view width is 1440 physical pixels, 1 lpx is 2 physical pixels. For details, see lpx.
``` { ... "window": { "designWidth": 720 } ... } ``` ## mode The **"mode"** configures the running type and syntax style of a JS component. The following attributes are supported:

Type

Default Value

Description

type

-

Running type of the JS component. The options are as follows:

  • pageAbility: Run the JS component in ability mode.
  • form: Run the JS component as a service widget.

syntax

-

Syntax type of the JS component. The options are as follows:

  • hml: compiled in the .hml, .css, or .js style.
  • ets: compiled in the declarative syntax style.
>![](../public_sys-resources/icon-note.gif) **NOTE:** >If **type** is set to **form**, **syntax** cannot be **ets**. ## Example config.json: ``` { "app": { "bundleName": "com.example.player", "version": { "code": 1, "name": "1.0" }, "vendor": "example" }, "module": { "js": [{ "name": "default", "pages": [ "pages/index", "pages/detail" ], "window": { "designWidth": 720 }, "mode": { "type": "pageAbility", "syntax": "ets" }, }], "abilities": [{ ... }] } } ```