> For the complete documentation index, see [llms.txt](https://docs.verygoodsecurity.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verygoodsecurity.com/vault/developer-tools/vgs-collect/js/formatting.md).

# Formatting

![VGS Collect.js masked input](/files/VVUrsa9lQroiFyzPRg19)

## Serializers

Use serializers to change the format of the data being sent to the server.

*Examples:*

{% code title="Replace value" %}

```javascript
form.field('#space-for-my-field', {
    serializers: [{ name: 'replace', options: { old:' ', new:'-' }}],
    serializers: [{ name: 'replace', options: { old:' ', new:'-', count: '2' }}]
});
```

{% endcode %}

{% code title="Expiration date separator" %}

```javascript
form.field('#space-for-my-field', {
    serializers: [{ name: 'separate', options: { monthName: 'month', yearName: 'year' }}]
});
```

{% endcode %}

{% code title="Convert to base64" %}

```javascript
form.field('#space-for-my-field', {
    type: 'file'
    serializers: [{ name: 'toBase64'}]
});
```

{% endcode %}

* [.field()](/vault/developer-tools/vgs-collect/js/reference-documentation.md#api-formfield)
* [Reference Documentation](/vault/developer-tools/vgs-collect/js/reference-documentation.md)

## Custom masking

An input mask refers to a string expression, defined by a developer, that constrains user input. This method is available for those types of fields: `text`, `textarea`, `password`, `zip-code`.

Example:

```javascript
f.field('#ssn .field-space', {}).mask('999-99-9999', '*');

f.field('#random-mask .field-space', {}).mask('XXXXX', null, {'X': '[0-9]'});
```

* [.mask()](/vault/developer-tools/vgs-collect/js/reference-documentation.md#api-formcardcvcfield-16)
* [Reference Documentation](/vault/developer-tools/vgs-collect/js/reference-documentation.md)

## Define string replace pattern

Method returns a new string with some or all matches of a pattern replaced by a replacement. This method is available for those types of fields: `text`, `textarea`, `password`, `zip-code`.

Example:

```javascript
f.field('#letters-only .field-space', {}).replacePattern('/[^a-zA-Z\s]+/g');

f.field('#numeric-only .field-space', {}).replacePattern('/[^\d]+/g');
```

* [.mask()](/vault/developer-tools/vgs-collect/js/reference-documentation.md#api-formcardcvcfield-16)
* [Reference Documentation](/vault/developer-tools/vgs-collect/js/reference-documentation.md)

## More examples

* [Control expiration date year length](/vault/developer-tools/vgs-collect/js/samples.md#control-expiration-date-year-length)
* [Separate month and year for the card expiration date field](/vault/developer-tools/vgs-collect/js/samples.md#separate-month-and-year-for-the-card-expiration-date-field)
* [Change expiration date separator](/vault/developer-tools/vgs-collect/js/samples.md#change-expiration-date-separator)


---

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