---
title: "Forms - Custom Form Validation (JavaScript)"
slug: "forms-custom-form-validation-javascript"
updated: 2023-03-22T22:14:01Z
published: 2023-03-22T22:14:01Z
canonical: "docs.interprose.com/forms-custom-form-validation-javascript"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.interprose.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom Form Validation (JavaScript)

## **Validate Data**

- Use Custom JavaScript to verify data exists or meets expectations
- Display an error if valid data doesn't exist when saving the completed form

## **Custom JavaScript**

Must be entered and saved to the form's Custom Validation section

### **Setup**

Custom Validation can be entered under **Setup -Forms -Form -Selected Form Custom Validation (JavaScript)** section

![mceclip2.png](https://cdn.document360.io/6c7303ca-5ffc-4149-8868-8ea498eee635/Images/Documentation/javaform.png?sv=2026-02-06&spr=https&st=2026-10-31T16%3A38%3A17Z&se=2026-10-31T17%3A38%3A17Z&sr=c&sp=r&sig=I%2B6V6MkIo1LSgoyOqklAqDp%2FJ5WSibUCAkkRKQowDEQ%3D)

Here is an example of Custom Validation JavaScript:

```
if (form.lookupFieldValue("VERIFY_ADDRESS") === "1" && form.lookupFieldValue("CORRECT_MAILING_ADDRESS") === ""){errors.add("An address must be entered, before this record can be saved");}
```

<font color="#0000ff" size="2" style="box-sizing: border-box;"><strong style="box-sizing: border-box; font-weight: bold;"><em style="box-sizing: border-box;"><span style="font-family: Arial;">Watch the video below for additional guidance.</span></em></strong></font>