How to create a file instannce using HTML 5 file API?

How to create a file instance in IE environment?

var b = newBlob(["foobarbazetcetc"], { type: "text/plain"});
var g =newFile([b], "test.txt");   /*** this always failed****/

It looks like IE (11) does not support calling File constructor. Similar code works with other browsers such as Chrome.

Since File is a thin wrapper around Blog, can I write a duck typing File to replace it?

Thanks.