Question about uploading files using Jquery and sending to c# webmethod

Question about uploading files using Jquery and sending to c# webmethod

I need to upload files using a Jquery call. Anyone have success doing this. 

 $("#chkBtn1").click(function () {
        var daFile = $("#file1").prop("files")[0];
        // Append form data  
        var form_data = new FormData();
        form_data.append("file", daFile);

        $.ajax({
            url: "testFileLoad1.aspx/processImages",
            //dataType: 'json',
            cache: false,
            contentType: "multipart/form-data",
            processData: false,
            data: form_data,
            traditional: true,                     // Setting the data attribute of ajax with file_data
            type: 'post',
            success: function (response) {
                alert('Success');
                console.log(response);
            },
            error: function (response) {
                alert('Error!');
                console.log(response);
            }
        })

Would this be the correct syntax and also where can I find sample code to process the file in the Webmethod call. I've tried the sytnax below.

I've tried this but it appears to not process the file.

    [WebMethod]
    public static string processImages(HttpContext htp1)
    {
        string Files = htp1.Items.ToString();
        HttpPostedFile f1 = htp1.Request.Files["file1"];
        return "Successful"

      }

Any ideas.