获取当前页面的pdf MVC 5

I am trying to get a pdf of a div in my view.

I am doing the following: I get the element, uri encode its html, then pass it to a method via ajax:

AJAX:

function getPDF(html) {
    $.ajax({
        type: "POST",
        url: "@Url.Action("printPage")",
        data: { html: encodeURIComponent(html) }

    }).done(function (result) {
        window.open("data:application/pdf; " + result);
        $("#printArea").html(result);
    }).fail(function (data) {
        alert("Failed");
    });
}

Method:

[HttpPost]
public void printPage(string html)
{
    String decoded = System.Uri.UnescapeDataString(html);
    var cd = new System.Net.Mime.ContentDisposition
    {
        FileName = "something.pdf",
        Inline = false
    };
    Response.AppendHeader("Content-Disposition", cd.ToString());
    var mem = Bcs.Common.Utilities.HTMLtoPDF.getPDF(decoded);
    //var base64EncodedPDF = System.Convert.ToBase64String(pdfByteArray);
    Response.BinaryWrite(mem.ToArray());
    //return File(mem, System.Net.Mime.MediaTypeNames.Application.Octet);
}

In the end I get a popup to open a pdf but it won't open, according to adobe acrobat it is corrupt.

I tried sending the html as a perameter to the method, but the perameter is too long

HTTP Error 404.15 - Not Found The request filtering module is configured to deny a request where the query string is too long.

What would be a good way of doing this.

public JsonResult printPage(String html)
        {
            String decoded = System.Uri.UnescapeDataString(html);
            var cd = new System.Net.Mime.ContentDisposition
            {
                FileName = "something.pdf",
                Inline = false
            };
            var mem = Bcs.Common.Utilities.HTMLtoPDF.getPDF(decoded);
            mem.Flush();
            mem.Position = 0;
            String b64Converted = Convert.ToBase64String(mem.ToArray());
            return Json(b64Converted, JsonRequestBehavior.AllowGet );

System.Net.Mime.MediaTypeNames.Application.Octet); }

Then in the view:

 $.ajax({
            type: "POST",
            url: "@Url.Action("printPage")",
            data: { html: encodeURIComponent(html) },

        }).done(function (result) {

            $("#printArea").append('<a href="data:application/pdf;base64,' + result + '">PDF</a>');
        }).fail(function (data) {
            alert("Failed");
        });

Apparently its very easy Just base64 the pdf and send it over at the json response.