Change Placeholder Text using jQuery

Question

I am using a jQuery placeholder plugin(https://github.com/danielstocks/jQuery-Placeholder). I need to change the placeholder text with the change in dropdown menu. But it is

Answer 1

$(document).ready(function(){ 
  $('form').find("input[type=textarea], input[type=password], textarea").each(function(ev)
  {
      if(!$(this).val()) { 
     $(this).attr("placeholder", "Type your answer here");
  }
  });
});

Copy and paste this code in your js file, this will change all placeholder text from whole site.