Show a pdf stream in a new window

I'm generating in a server a PDF document that I want to show then in the client. The server side looks like following:

ByteArrayOutputStream baos = generatePDF();
response.setContentType("application/pdf");
response.setHeader("Content-Disposition", "attachment; filename=file.pdf");
response.setContentLength(baos.size());
baos.writeTo(response.getOutputStream());

In the client, I have the following code to get retrieve the PDF:

$.ajax({
    type: "POST",
    url: url,
    data: {"data": JSON.stringify(myData)},
    success: function(data, textStatus, jqXHR) {
        window.open("data:application/pdf," + escape(data));
    },
    error: function(jqXHR) {
        showError("...");
    }
});

It looks well, the new window is opened, but the PDF is not shown. It always appears an empty document.

Nevertheless, if the client looks like following, it works fine:

var form = $("<form target='_blank'>").attr({
    action : myURL,
    method : "POST"
});
var input1 = $("<input type='hidden'>").attr({
    "name": "data",
    value: JSON.stringify(myData)
});

form.append(input1);
$("body").append(form);
form.submit();
form.remove();

But I can't use the second way cause I need to manage the errors, and I can't do it using form.submit().

Any idea about what's happening with the PDF?