$form->isblank("transdate", $locale->text("Invoice Date missing!"));
$form->isblank("duedate", $locale->text("Due Date missing!"));
$form->isblank("vendor", $locale->text('Vendor missing!'));
$form->isblank("transdate", $locale->text("Invoice Date missing!"));
$form->isblank("duedate", $locale->text("Due Date missing!"));
$form->isblank("vendor", $locale->text('Vendor missing!'));