Make attachment mandatory in SharePoint list form

Process:
1. Go to the SharePoint "Default New Form"

2. Edit the page.
3. Add a script editor web part.
4. Add the below script to the web part and close.

<script type="text/javascript" language="javascript">

function PreSaveAction() {

    if (document.getElementById('idAttachmentsRow').style.display=='none' )

    {

        alert('Attachment is Mandatory! Please attach Documents.');

        return false ;

    }

    else {  return true;  }

}

</script>

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