Pass javascript local variable into rails tag

I want pass the javascript variable into rails tag. Here my code

function add_questionfield(obj)
{
  var last_id = $('input[type="text"]:last').size();
  last_id++;
  alert(last_id);
  $(".question_div_<%= @subjectModuleId %>").show();
  $(".question_div_<%= @subjectModuleId %>").append('<%=text_field_tag "question_'+ last_id +'",@question.question, name: 'questions[]',class:'form-control', placeholder:'Type Question Here',
                                                 :maxlength => 200,:autocomplete => :off %>');
}

Here I pass last_id into rails tag.

Expected id was question_2

How to solve this. Thank you But its generate question_last_id