How can I skip entries with vat amount on page?

Dear developers,
I want to show entries without vat amount from GL entry on page. How to skip these entries
Group by document no. and filter vat Amount
I tried onOpenpage
Glentry.setfilter(docno,docno)
Glentry. Setfilter(amount,’<>%1’,0)
If Glentry.findset then repeat
Skip;
Until glentry.next=0