1# CustomData (System API)
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3When starting a modal page, you can transfer custom data to the autofill service through [reloadInModal](js-apis-inner-application-autoFillExtensionContext-sys.md) and obtain the data through [onFillRequest](js-apis-app-ability-autoFillExtensionAbility-sys.md) of the service.
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5> **NOTE**
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7> The initial APIs of this module are supported since API version 12. Newly added APIs will be marked with a superscript to indicate their earliest API version.
8> The APIs of this module can be used only in the stage model.
9> The APIs provided by this module are system APIs.
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11##  Properties
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13**System capability**: SystemCapability.Ability.AbilityRuntime.AbilityCore
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15| Name | Type                  | Mandatory | Description                                                |
16| ---- | ---------------------- | ---- | ---------------------------------------------------- |
17| data | Record<string, Object> | Yes  | Custom data transferred for starting the modal page. The data is of the Record type. |
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