[jquery] Javascript how to split newline

The problem is that when you initialize ks, the value hasn't been set.

You need to fetch the value when user submits the form. So you need to initialize the ks inside the callback function

(function($){
   $(document).ready(function(){
      $('#data').submit(function(e){
      //Here it will fetch the value of #keywords
         var ks = $('#keywords').val().split("\n");
         ...
      });
   });
})(jQuery);