The cls-utm.js file can be utilized with forms to automatically populate hidden input fields with UTM parameters, which are used to track the source of website traffic. This can be useful for tracking the effectiveness of marketing campaigns and understanding where website traffic is coming from.

The UtmForm class defined in cls-utm.js provides several methods for adding UTM parameters to forms. The addFormElem method is used to add a hidden input field to a form with a given name and value. The getFieldEl method is used to get the HTML element for a hidden input field with a given name and value. If the form already has a hidden input field with the same name as the field name we are trying to add, then the value of the existing field is updated. If the form does not have a hidden input field with the same name, then a new hidden input field is added to the form.

One benefit of using cls-utm.js with forms is that it allows website owners to track the source of website traffic more accurately. By automatically populating hidden input fields with UTM parameters, website owners can ensure that UTM parameters are included in form submissions. This can help website owners to better understand where their website traffic is coming from and which marketing campaigns are most effective.

Another benefit of using cls-utm.js with forms is that it can save time and effort for website owners. Rather than manually adding hidden input fields to forms for each UTM parameter, website owners can use the UtmForm class to automatically add hidden input fields to forms. This can save time and reduce the risk of errors when adding UTM parameters to forms.