setInterval(function () {

    if($('input[name="city"]').val() != 'Perth')
    {

       $('input[name="city"]').val("Perth");
       $('input[name="city"]').attr('readonly',true);
       $('input[name="city"]').trigger('keyup');
       $('input[name="region"]').val("WA");
       $('input[name="region"]').attr('readonly',true);
       $('input[name="region"]').trigger('keyup');

    }

    },3000);