javascript - Confirm box depending on input value -

i'm new javascript don't judge hard (any suggestions or comments highly appreciated).

i have form in rails app (haml file):

= simple_form_for(@book, remote: true) |f|   .row   .form-group     = f.input :book_title, as: :string, label: "title of book"     %br     = f.input :pages_number, as: :string, label: "number of pages"     %br   .form-actions     = f.button :submit, "create", class: "btn btn-success"     = link_to t('buttons.cancel'), '#', onclick: "$.modal.close()", class: 'btn btn-warning pull-right' 

the action in controller opens form:

  def new     @book = book.new   end 

the action in controller saves form:

  def create   end 

what i'm trying check whether input number of pages bigger 10. i want create confirm box.

i trying save @pages_number = params[:pages_number] in create action, , use data: (@pages_number < 10 ? { confirm: "are sure?" } : nil) in view, didn't work.

do need use javascript in case?

always remember ruby = server; javascript = client

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if evaluating against condition set server, code work.

however, since you're evaluating against dynamically created condition, you'll need use javascript determine whether value worth invoking confirm dialogue:

#app/assets/javascripts/application.js $(document).on("ajax:beforesend", "#form", function(event, xhr, settings) {    var $el    = $(this);    var $pages = $el.find("input[name='page_numbers']");    if ($pages.val() > 10) {       var response = confirm($el.data('confirm') || 'are sure?'); // not sure if pull rails confirm       if (!response) { return; }    } }); 

the above, although needs tweaking, should evaluate inputted value page_numbers box. if user not confirm, return, preventing progress.

as you're using ajax, use ajax:beforesend hook interject before request sent ajax driver. if weren't using remote: true, you'd want @ binding form.on("submit" method.

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update

after lengthy chat discussion, resolved following:

#app/assets/javascripts/application.js function validateform() {  var x = $('.value').val();    if (x < 10) {      var res = confirm("are sure?");      if (res == false) { return false; }    }  }  #app/views/books/new.html.erb <%= form_for @book, onclick: "return validateform();", remote: true |f| %> 

we used this reference.