jquery循环获取每个表格的ID

<tr><td height="20"><inputtype="hidden"name="code">var value2;$(".row_id").each(function() {// $(".row_id").lengthvalue2 += $(this).val() + ",";});if ($.trim(value2)) {value2 = value2.replace("undefined", "");value2 = value2.substr(0, value2.length - 1);}alert(value2);