$(document).ready(function(){
    var courses = []
    $.ajax({
          url: "/course/list/json",
          context: document.body,
          datatype: 'json',
          success: function(json){
            $.each(json.courses, function(key, val) {
              courses.push(val)
            });
          }
    });

  $('#course-add :text').change(function() {

  for(i=0; i<courses.length; i++) {
    console.log("loopar")
    if(courses[i]==$(this).val()) {
      console.log("matchar")
      $(this).addClass('red')
    }
  }
  });
});