Try it like :
File.save(csvInput, function (content) {
var hiddenElement = document.createElement('a');
hiddenElement.href="https://stackoverflow.com/questions/20300547/data:attachment/csv," + encodeURI(content);
hiddenElement.target="_blank";
hiddenElement.download = 'myFile.csv';
hiddenElement.click();
});
based on the most excellent answer in this question