WS Service二进制文件对PDF的响应

Question

I have a WS that returns a binary response.

What i need is when i request the service through ajax request, getting the response and generate again the original pdf.

However i can generate the pdf, but i don't know why i'm not getting the pdf content.

    $.ajax({
          url: resource_str,
          type: "GET",
          async:   true,
        },
          success: function(data) {
        var file = new Blob([data], {type: 'text/plain'});
                        var fileURL = URL.createObjectURL(file);
                        window.open(fileURL);
                        var a = document.createElement("a");
                        a.href = fileURL;
                        a.download = "Testing.pdf";
                        document.body.appendChild(a);
                        a.click();
                        $(window).on('focus', function(e) {
                          $('a').remove();
                        });
        },fails: function (data){
          console.log('Error');
        }
    })

what am i doing wrong? Why i'm losing the content?

i'm debating with this question for a while. Everything i need is to stream the pdf as binary from the WS and next be able to generate the pdf again using jquery.