Prevent Catalog item Submission if there is no attachment

function onSubmit() {
    // Retrieve elements with the 'get-attachment' class using the document object
    var attachmentElements = this.document.getElementsByClassName('get-attachment');

    // Check if there are any attachment elements
    if (attachmentElements.length === 0) {
        // If no attachments are found, alert the user with a message and prevent submission
        alert("You must attach at lease one Document.");
        return false; // Block form submission
    }

    // If attachments exist, allow the form to be submitted
    return true;
}

Explanation

1. Retrieve Elements by Class Name:
   var attachmentElements = this.document.getElementsByClassName('get-attachment');

   • The this.document.getElementsByClassName method retrieves all HTML elements with the class name get-attachment.
   • The result is a live HTMLCollection, which is similar to an array and contains all matching elements on the form.
2. Check for Attachments:
   if (attachmentElements.length === 0) {

   • The length property checks how many elements were found with the class name get-attachment.
   • If the length is 0, it means no attachments are present.
3. Alert the User:
   alert("You must attach a Template Document.");
return false;

   • If no attachments exist, an alert message is displayed to inform the user that they must attach a document.
   • return false prevents the form from being submitted.
4. Allow Submission:
   return true;

   • If attachments exist, the function allows the form to be submitted by returning true.