I'd like to limit the extension of the uploaded files in a form. I've written a script in the On add > Validation to check the filename. That's works correctly :

    if (input.FileUploadField.endsWith(".jpg"))

    {

        show or hide some fields;

    } 

Now, I'd like to check the filename before submiting the form, using a script in the "On User Input" of my  FileUploadField , but the filename seems to be stay == "" and don't read the selected filename. Have you a suggestion for that please ?

Thanks !