急写在后台的input按钮怎么使用单击事件

急……写在后台的input按钮如何使用单击事件
 string table = "<table id='tableMain'>";
                    table += "<caption style='text-align:center;font-weight:bold'>任务名称：" + rwname + "</caption>";
                    string tr1 = "<tr><th><input type='text' readonly='readonly' value='采样地点' /></th>";
                    string tr2 = "<tr><th><input type='text' readonly='readonly' value='样品编号'/></th>";
                    string tr3 = "<tr><th><input type='text' readonly='readonly' value='采样时间' /></th>";
                    string tr4 = "<tr><th></th>";

                    string td1 = "";
                    string td2 = "";
                    string td3 = "";
                    string td4 = "";
                    foreach (DataRow dr in jcyp.Tables[0].Rows)
                    {
                        td1 += "<th><input type='text' name='ypname' readonly='readonly' value='" + dr[0] + "'/></th>";
                        td2 += "<td><input type='text' name='bianhao' value='" + dr[2] + "' /></td>";
                        td3 += "<td><input type='text' name='shijian' value='" + dr[3] + "' onfocus='WdatePicker()' /></td>";

                        td4 += "<td><input type="button" id="button1" runat="server" value="提交" class='btn'  /></td>";
                    }
                    td1 = tr1 + td1 + "</tr>";
                    td2 = tr2 + td2 + "</tr>";
                    td3 = tr3 + td3 + "</tr>";
                    td4 = tr4 + td4 + "</tr>";




在td4这个地方的input如何来写单击事件