我想设置一个默认日期,实际日期,例如我如何设置它？
<%= date_field_tag(:datetime_ida, value = nil, options = {})%>
另外,我如何在组合框中设置默认值
<%= select_tag :children_quantity, options_for_select([['0 Children', 0], ['1 Children', 1], ['2 Children', 2], ['3 Children', 3], ['4 Children', 4], ['5 Children', 5]], 1) %>
顺便说一句,date_field_tag和date_field之间有什么区别？