Pass question mark url with Ajax load in a div

I have a simple Ajax-load function that loads another php file into a div '#content_box' via a form. The month and year parameters are determined by respectively #dm and #dy. The submit button has passed the id #ds. I was wondering, what is the best way to pass these parameters to the browser url (i.e. how to obtain an url such as http://ift.tt/1CWY8Ip )?

$(document).ready(function(){
  $('#df').submit(function(){
    var month_ddchart = $('#dm').val();
    var year_ddchart = $('#dy').val();
    source_ddchart = '/data/ddc-'+month_ddchart+'-'+year_ddchart+'-body.php';
    $('#content_box').load(source_ddchart);
    event.preventDefault();
  });
});