Set the Zip Attachments Field Checked by Default on the New Email Message Window

Solution:
1. Open Notepad and enter the script below:
function zipAttach(type, form, request)
{
 nlapiSetFieldValue('compressattachments', 'T');
}

2. Click File > Save As:

          a. File name =  [Name].js

          b. Save as type = All Files     

3. Click Save.

4. In NetSuite, navigate to Customization > Scripting > Scripts > New.

5. Select User Event.

6. Provide a name for this script.

7. In the Scripts tab, select the .js file in the Script File field.

8. In the Scripts tab, set the Before Load Function field to zipAttach.

9. Click Save and Deploy.

11. On the New Script Deployment Page, set the following:

           a. Applies To field is Message

           b. Deployed checkbox is checked

           c. Status is Released

           d. Log Level is Debug

           e. Execute as Admin checkbox is checked

           f. Audience tab > Roles > Select All checkbox is checked
          
12. Click Save.