---
id: post/aardvarklabs-blog/3680
type: post
title: Step-by-Step Guide to Custom User Controls in Business Central
summary: Custom user controls in Business Central use HTML, JavaScript, and AL to create bespoke UI components beyond standard controls. The post demonstrates building a star rating control for vendors, covering the control addin definition, JavaScript implementation, and AL page integration.
tier: community
language: en
tags:
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  - html/javascript
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    quote: User controls are the way that users interact with the system.
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    title: Step-by-Step Guide to Custom User Controls in Business Central
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    quote: These are small HTML and JavaScript components we can create to add user interfaces to Business Central.
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    title: Step-by-Step Guide to Custom User Controls in Business Central
    date: "2026-06-26"
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    quote: You can create entire bespoke interface systems to meet specific data entry needs.
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post_id: "3680"
source_id: aardvarklabs-blog
source_name: Aardvark Labs
url: https://aardvarklabs.blog/2026/06/26/step-by-step-guide-to-custom-user-controls-in-business-central/
published_at: "2026-06-26T12:00:00.000Z"
author: Marcel Chabot
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words: 1449
quotes:
  - text: User controls are the way that users interact with the system.
    why_it_matters: Establishes that controls are the fundamental mechanism for user interaction in Business Central
  - text: These are small HTML and JavaScript components we can create to add user interfaces to Business Central.
    why_it_matters: Clarifies that custom user controls are web-based components integrated into BC for enhanced UX
  - text: You can create entire bespoke interface systems to meet specific data entry needs.
    why_it_matters: Shows the broader potential of user controls beyond simple examples
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# Step-by-Step Guide to Custom User Controls in Business Central

[Read the post](https://aardvarklabs.blog/2026/06/26/step-by-step-guide-to-custom-user-controls-in-business-central/) · Aardvark Labs (Marcel Chabot) · 2026-06-26 · 1449 words · tier community · reviewed (checked by Opus)

> Custom user controls in Business Central use HTML, JavaScript, and AL to create bespoke UI components beyond standard controls. The post demonstrates building a star rating control for vendors, covering the control addin definition, JavaScript implementation, and AL page integration.

## Key points

- User controls bridge AL and JavaScript to extend Business Central's UI capabilities with custom HTML and CSS components
- Control addins declare events and procedures that enable bidirectional communication between JavaScript and AL code
- The startup script initializes the control and signals readiness via OnControlReady event before AL can interact with it
- Data flows from AL to JavaScript through procedures like SetRating, and from JavaScript to AL through events like OnRatingChanged
- Proper state management with flags prevents recursion when updating controls from both AL and user interactions

## Quotes

- "User controls are the way that users interact with the system." (Establishes that controls are the fundamental mechanism for user interaction in Business Central)
- "These are small HTML and JavaScript components we can create to add user interfaces to Business Central." (Clarifies that custom user controls are web-based components integrated into BC for enhanced UX)
- "You can create entire bespoke interface systems to meet specific data entry needs." (Shows the broader potential of user controls beyond simple examples)

## AL objects mentioned

As named in the post. A name that matches one object page by exact type and name links to it; the others stay as named.

- other "ARDVendorRatingControl"
- [page 26 "Vendor Card"](../../objects/page/26.md)

## Context

- Features: user controls, control addins, custom UI components, event handling, AL-JavaScript bridge, vendor rating control

Source: Aardvark Labs, community blog. Summary, key points and quotes are derived (CONTENT-NOTICE.md); read the original for the full text.