       # On Sequence change, fire custom event "sequence:change" on element.
       # Added for aborting video bufferization, see ../video/10_main.js
       @el.trigger "sequence:change"
+      #20151026b If the parameter from url equal to "0", then change the value of new_positon and save to DB
+      if @prev_button_para == "0"
+        @prev_button_para = null
+        new_position = @num_contents
+        modx_full_url = @modx_url + '/' + @id + '/goto_position'
+        $.postWithPrefix modx_full_url, position: new_position
       @mark_active new_position
       @$('#seq_content').html @contents.eq(new_position - 1).text()
       XModule.loadModules(@$('#seq_content'))

    @num_contents = @contents.length
    @id = @el.data('id')
    @modx_url = @el.data('course_modx_root')
    @initProgress()
    @bind()
    @render parseInt(@el.data('position'))

    if @position == 1
      if prev_section != null
        @$('.sequence-nav-buttons .prev a').removeClass('disabled').click(()=>
          #20151026b Add parameter 0 at the end of url
          window.location.href = prev_section + "0"
        )
      else
        @$('.sequence-nav-buttons .prev a').addClass('disabled')
