Is there a way to stop IE10/IE11 from showing open or save prompt

I am downloading files from server using javascript blob something like

let blob = new Blob([resposne['_body']], { type: contentType });
if (navigator.msSaveBlob) {
    navigator.msSaveOrOpenBlob(blob, fileName); // in case of IE
} else {
    let objectUrl = window.URL.createObjectURL(blob);
    window.open(objectUrl);
}

The code above works fine but in IE it shows a dialog:

Also if I put a direct pdf link in the href tag then it also works fine. So it looks like there is no problem with the adobe plugin.

What I want is to directly open the file instead of showing this prompt. I tried Registry hack as suggested here but did not have any luck. Any idea how to achieve this?