Help with js code to remove upload attachment box on submit request form

Hi, 

Please forgive my lack of knowledge here. I've looked at the advice for hiding the upload attachment area of the ticket form on Guide on multiple threads and comments and have a bit of code that has worked for other users however it does not seem to work and the script has changed significantly since then and I can't see any newer guidance on how to hide this area. 

As per the guidance, I'm adding this code to my script.js 

// hide attachments 
if (window.location.href == "https://XXbrandURLXX.zendesk.com/hc/en-gb/requests/new?ticket_form_id=XXumber hereXX") { 
   $('.form-field label:contains("Attachments")').hide();
   $('#upload-dropzone').hide();

However in preview it is not working.  I can't switch off the option in overall settings as we still want attachments; I just don't want it on this specific form that sits on another brand within our ZD.