Access HTML Table Cell (TD) values in Code Behind (Server Side) in ASP.Net

Here I have created sample that will help you out.we can not get value to companyInfo by FindControl as we appending rows using jquery.so i have used HiddenFiled.

HTML

<div>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
    <script type="text/javascript">
        $(function () {
            SetEmptyMessage();
            $("[id*=cbSelect]").on("click", function () {
                var selected = $('[id$=gvCompanyListing] tr td input[type=checkbox]:checked');
                if (selected.length > 0) {
                    $(selected).each(function () {
                        var appendRow = $(this).closest('tr').clone(true);
                        var row = $(this).closest('tr');
                        $(row).remove();
                        $("[id$=tblAssigned]").append(appendRow);
                    });
                    SetEmptyMessage();
                    return false;
                }
                else {
                    var selected = $('[id$=tblAssigned] tr td input[type=checkbox]:not(:checked)');
                    if (selected.length > 0) {
                        $(selected).each(function () {
                            var appendRow = $(this).closest('tr').clone(true);
                            var row = $(this).closest('tr');
                            $(row).remove();
                            $("[id$=gvCompanyListing]").append(appendRow);
                        });
                    }
                    SetEmptyMessage();
                    return false;
                }
            });
        });
        function SetEmptyMessage() {
            if ($('[id$=tblAssigned] td').closest('tr').length == 0) {
            } else {
                $('[id$=tblAssigned]').find('.empty').remove();
            }

            if ($('[id$=gvCompanyListing] td').closest('tr').length == 0) {
            } else {
                $('[id$=gvCompanyListing]').find('.empty').remove();
            }
        }

        function GetSelectedCompany() {
            var selectedCompanies = [];
            $('[id$=tblAssigned] tr').each(function () {
                selectedCompanies.push($('td', $(this)).eq(1).html());
            });
            $('[id*=hfSelectedCompanies]').val(selectedCompanies.join(','));
        }
    </script>
    <asp:GridView ID="gvCompanyListing" runat="server" AutoGenerateColumns="False" GridLines="None">
        <Columns>
            <asp:TemplateField HeaderText="Select">
                <ItemTemplate>
                    <asp:CheckBox ID="cbSelect" CssClass="gridCB" runat="server"></asp:CheckBox>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="client_name" SortExpression="CompanyInfo" ItemStyle-Height="1px"
                ControlStyle-CssClass="companyInfo" HeaderText="CompanyInfo"></asp:BoundField>
        </Columns>
    </asp:GridView>
    <br />
    <table id="tblAssigned" runat="server">
    </table>
    <br />
    <br />
    <asp:HiddenField ID="hfSelectedCompanies" runat="server" />
    <asp:Button ID="Button1" Text="RequestAccess" runat="server" OnClick="btnRequestAccess_Click"
        OnClientClick="GetSelectedCompany()" />
</div>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("client_name");
        dt.Rows.Add("abc");
        dt.Rows.Add("bbc");
        gvCompanyListing.DataSource = dt;
        gvCompanyListing.DataBind();
    }
}

protected void btnRequestAccess_Click(object sender, EventArgs e)
{
    System.Text.StringBuilder strBuild = new System.Text.StringBuilder();
    //string strUserName = Session["UserName"].ToString();
    // int nUserName = strUserName.Length;
    //int nRemaing = nUserName - 21;
    //string strActualName = strUserName.Substring(21, nRemaing);
    strBuild.Append("Request to set Clients to Hays user " + "Kevin" + Environment.NewLine);
    int nval = 0;
    HtmlTable tbl = (HtmlTable)form1.FindControl("tblAssigned");

    for (int i = 0; i < this.hfSelectedCompanies.Value.Split(',').Length; i++)
    {
        strBuild.Append(this.hfSelectedCompanies.Value.Split(',')[i] + Environment.NewLine);
        nval = nval + 1;
    }   
}

Screenshot