# How it Works

Postcode Lookup can be attached to any form with pre-existing address inputs and an empty container to render the Postcode Lookup UI.

When initialised it will:

1. Identify the context container defined by [`context`](https://postcode-lookup.ideal-postcodes.co.uk/classes/Controller.Controller-1.html#context)

2. Render the Postcode Lookup UI within the context container including:

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   1. Postcode Lookup text field
   2. Postcode Lookup button
   3. Container to render address list
   4. Message container

3. Pipe address results to the fields defined in `outputFields`.

4. Perform a key check to determine whether it is usable. If the check fails, initialisation is aborted. Use the `onCheckFailed` callback to update your page for manual address entry.