How Make attachment mandatory using Script and it should be work Both in Native UI and Portal?

[Raviteja24]

Hi,

I have created a onSubmit client script which is used to make attachment mandatory . But , it was working in portal and it is not working in backend.

It was showing error in backend 

Thanks,

[Community Alums]

Hi Anand,

I have also tried this, but this is not working.

Thanks,

Aman