///////////////////////////////
// all jQuery stuff here 

$(document).ready(function() {
  
  $("#trigger").click(function() {
  $("#demo").html("Hello, World!");
  });

  $(document).on('change', 'select', function(){
    alert($(this).find('option:selected').text());
    
  });


});


//go back+go forward buttons
  function goBack() {
    window.history.back();
  }
  function goForward() {
    window.history.go(1);
  }



//to switch divs inside the container div

  function show(param_div_id) {
    document.getElementById("container").innerHTML = document.getElementById(param_div_id).innerHTML;
  }