Web Development

public class ApiSampleUploadController : ApiController
   {


       [HttpPost]
       public string Test(HttpPostedFileBase file )
       {

           return "Success";
       }


   }

@using (Html.BeginForm("Submit"))
 {
 /*code*/
     //FileUpload
       <div>
        <input type="file" name="file" id="uploadFile" />
      </div>
/*code*/
 }

$('#uploadFile').on("change", function () {
    var formdata = new FormData($('form').get(0));

    CallUpload(formdata);
});


function CallUpload(file) {
    console.log(file);
    $.ajax({
        url: '/api/ApiSampleUpload/Test',
        type: 'POST',
        data:  'file=' + file ,
        cache: false,
        processData: false,
        contentType: 'application/json',
        success: function () {
            alert('Success');
        },
        error: function () {
            alert('Error occured');
        }
    });
}

private static async Task TestWebAPI(string url)
{
    using (var client = new HttpClient())
    {
        using (var httpResponse = await client.GetAsync(url))
        {
            try
            {
                httpResponse.EnsureSuccessStatusCode();     //<=======EXCEPTION HERE
                string responsContent = await httpResponse.Content.ReadAsStringAsync();
            }
            catch (Exception e)
            {
                _logger.Log(LogLevel.Error, e);
            }
        }
    }
}

I need to in the end figure out how to compose PHP code. I've begun with learning HTML as CSS and am interested in what extent other individuals spent learning HTML and CSS before moving onto PHP. Simply searching for some heading and any tips you folks can give.