I have a button that submits a form remotely with Ajax using the rails built in helpers:

```
  button_to 'Delete Document', [:proofreader, proofreading_job, proofread_document], 
               method: :delete, 
               remote: true,  
               class: "btn btn-danger btn-sm", 
               data: { disable_with: "Deleting document..." }

```

When the form is submitted to the controller I can cause an alert to show as follows:

```
def destroy
  @proofread_document.destroy
  respond_to do |format|
    format.js { render js: "alert('The username to be displayed is:')"}
  end
end

```

However when I want to render the destroy.js.erb file which has no code in it yet I get the following error in the browser:

```
def destroy
  @proofread_document.destroy
  respond_to do |format|
    format.js
  end
end

Uncaught SyntaxError: Unexpected token <
    at processResponse (rails-ujs.self-ed0b535c2816e34ce8dee0346bd17387dffd4873cb347fa9a8b267dae6f7f41b.js?body=1:257)
    at rails-ujs.self-ed0b535c2816e34ce8dee0346bd17387dffd4873cb347fa9a8b267dae6f7f41b.js?body=1:186
    at XMLHttpRequest.xhr.onreadystatechange (rails-ujs.self-ed0b535c2816e34ce8dee0346bd17387dffd4873cb347fa9a8b267dae6f7f41b.js?body=1:241)

```

How can I fix this problem its stopped all development on this project.