pagechange event not firing

pagechange event not firing

New to jquery. The pagechange event doesn't appear to be firing when I change pages.
Using this to change page.
 
 $('#getjumps').submit(function(e){
      $.mobile.changePage('#page4', { changeHash : "true"});
   e.preventDefault();
  });


 
using this on the page changed to:
 
$('#page4').on('pagechange', function(event){
  $('#uspabutton').text("#" + $.cookie('uspanumber'));
  $('#jumplist').listview('refresh');
  alert("refreshed pagechange"); 
});



 
never fires. Pageinit fires the first time I go to the page, but when I go back to page 1, then return to page4, nothing seems to fire, init or page change.
Thanks