Sharepoint 2013-Minimal Download Strategy.

 <script type="text/javascript">

function uploadFile() {

  var fileInput = document.getElementById("fileInput");

  var file = fileInput.files[0];

  

  if (file) {

    var context = SP.ClientContext.get_current();

    var web = context.get_web();

    var list = web.get_lists().getByTitle("Your List Name");

    var folder = list.get_rootFolder();

    

    context.load(folder);

    

    // Read the file data

    var reader = new FileReader();

    

    reader.onloadend = function (evt) {

      if (evt.target.readyState == FileReader.DONE) {

        // Create a new file creation information object

        var fileInfo = new SP.FileCreationInformation();

        fileInfo.set_url(file.name);

        fileInfo.set_content(new SP.Base64EncodedByteArray());

        

        // Convert the file data to byte array

        var byteArray = new Uint8Array(evt.target.result);

        

        for (var i = 0; i < byteArray.byteLength; i++) {

          fileInfo.get_content().append(byteArray[i]);

        }

        

        // Upload the file to the list

        var uploadedFile = folder.get_files().add(fileInfo);

        

        context.load(uploadedFile);

        

        // Execute the upload request

        context.executeQueryAsync(

          function () {

            // File uploaded successfully

            console.log("File uploaded successfully");

          },

          function (sender, args) {

            // Error occurred while uploading file

            console.log("Error uploading file: " + args.get_message());

          }

        );

      }

    };

    

    // Read the file as an ArrayBuffer

    reader.readAsArrayBuffer(file);

  }

}

</script>

<!-- HTML Markup -->

<input type="file" id="fileInput" />

<button onclick="uploadFile()">Upload</button>