Dimitriy

Modernizr.load([
  {
    test: 320 >= window.screen.width,
    yep:   "big.js",
    nope: ["small.js", "small.css"]
  }
]);

<div class="msg"></div>
<div class="form-wrap" style="display:block">
<%= form_tag('/feedback', remote: true, format: :json, id: 'feedback') do %>
....

def send_email
....
  respond_to do |format|
    # if success
    msg = success ? 'You request will be success processed'
                  : 'Ooops. Error occurred. Try later.'
    format.json { render json: {msg: msg}.to_json }
  end
end

$('#feedback')
  .on 'ajax:before', ()->
    $('.form-wrap').hide()
    $('.msg').html('Sending...')
  .on 'ajax:success', (e, data)->
    $('.msg').html(data.msg)

.wrap{
        position: relative;
    }
    .wrap-scroll{
        margin-left: 100px;
        width: 300px;
        overflow: auto;
    }
    table{
        width: 500px;
    }
    table td{
        width: 100px;
        border: 1px solid #ccc;
    }
    table tr td:first-child{
        width: 100px;
        position: absolute;
        left: 0px;
        z-index: 100;
    }

<div class="wrap">
    <div class="wrap-scroll">
        <table>
            <tbody>
                <tr>
                    <td>Col-1</td>
                    <td>1</td>
                    <td>2</td>
                    <td>3</td>
                    <td>4</td>
                    <td>5</td>
                </tr>
                <tr>
                    <td>Col-2</td>
                    <td>1</td>
                    <td>2</td>
                    <td>3</td>
                    <td>4</td>
                    <td>5</td>
                </tr>
            </tbody>
        </table>
    </div>
</div>