You ca try to replace your submit button by a normal button and to put a script like bello on click event:
event.target.submitForm({cURL: "mailto:"+
$record.processDatas.processEmail.value +
"?subject=" + $record.processDatas.processSubject.value ,
bEmpty: true, // Post all fields (true), or do Not post all fields (false)
cSubmitAs: "PDF", // Post PDF format
cCharset: "utf-8"});
Hope this help.