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The Advanced tab of the form settings page contains JavaScript snippets for programmatically updating and retrieving data from your embedded Conversion form.
These settings only apply to embedded Conversion forms.
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Form fields

This table maps each form field (both displayed and hidden fields) to its field ID, which is used to identify it programmatically.

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Listen to form submissions

The following JavaScript snippet shows how to retrieve submitted form field values from an embedded Conversion form. 
// Optional helper to access fields by their readable names
const FORM_FIELDS = {
  email: "<FIELD_ID>",
  name: "<FIELD_ID>",
};

window.addEventListener("message", (event) => {
  if (event.data?.type === "conversion-forms" && event.data.data?.eventName === "submitted") {
    const fields = event.data.data.fields || {};
    console.log("Form submitted:", fields);

    // Example of pulling specific values:
    // console.log("Email:", fields[FORM_FIELDS.email]);
  }
});
Replace <FIELD_ID> with your form field ID’s
Steps to retrieve fields programmatically:
1

Define a helper object

Define a helper object to store the field IDs for each field. These IDs are used to reference field data in your code.
2

Wait for form submission

Add an event listener for the submitted event, which fires when the form has been submitted.
3

Read the submitted fields

Extract values from the fields object, which maps each field ID to its submitted value.

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Update field values

The following JavaScript snippet shows how to programmatically update field values on an embedded Conversion form. 
// Optional helper to access fields by their readable names
const FORM_FIELDS = {
  email: "<FIELD_ID>",
  name: "<FIELD_ID>",
};

// Ensure the form is ready to receive messages
window.addEventListener("message", (event) => {
  // Only handle messages from Conversion Forms
  if (event.data?.type !== "conversion-forms-ping" || event.origin !== "https://forms.conversion.ai") return;

  document.getElementById(<YOUR_FORM_ID>)?.contentWindow.postMessage({
    type: "conversion-forms",
    data: {
      eventName: "set-values",
      fields: {
        // Set a value
        // [FORM_FIELDS.email]: "user@example.com",
        // Remove a value
        // [FORM_FIELDS.name]: null
      }
    }
  }, "https://forms.conversion.ai");
});
Replace <YOUR_FORM_ID> with your form ID, and <FIELD_ID> with your form field ID’s
Steps to set field values programmatically:
1

Define a helper object

Define a helper object to store the field IDs for each field. These IDs are used to target specific fields when setting values.
2

Wait for the form to render

Add an event listener for the "conversion-forms-ping" event, which fires when the form is ready to receive messages.
3

Post a message to the iframe

Send a message to the form iframe with a fields object mapping each field ID to the value you want to set.
To clear a field, set its value to null