JavaScript works in Act-On, but not everywhere — some components block it outright for security and deliverability reasons, while others support it by design.
Why this matters: If your custom script or tracking code silently disappears after you save, it's usually not a bug — it's Act-On stripping JavaScript from an area that doesn't support it. Knowing which areas do support it saves you from troubleshooting the wrong thing.
Where JavaScript Is Blocked
- JavaScript is never permitted in email messages and will be automatically removed by Act-On if detected in an email being sent out.
- Many recipient email clients or email security appliances will remove JavaScript automatically from incoming mail, or not deliver/blocklist any mail containing JavaScript (due to security concerns).
- In the Legacy Email Composer, it is disabled in Custom Stationery, Custom Content Blocks, and Rich Text Blocks by default.
- It can be enabled in these areas if your account is configured with a subdomain.
Where JavaScript Is Supported
JavaScript is enabled and supported in other areas of Act-On.
- The External Web Analytics Support text area in a form's settings supports JavaScript by default. See the article Customizing Form Appearance and Functionality.
- The Script button in the Landing Page editor allows you to enter JavaScript.
- This will embed your script at the bottom of your landing page document.
- This is an appropriate solution for most third-party analytics codes (such as Google's various tracking scripts).
If JavaScript is entered into an unsupported section of Act-On (or if the enhanced JavaScript support is not enabled for your account), your scripts will be automatically removed or hidden. These restrictions are for security reasons, but the above-mentioned sections of the application which do support scripts make it possible to import your custom design or functionality.