gistfile1.js

jQuery.fn.extend({
  // upload file through iframe, without refreshing the page, must be wrapped by form
  // jquery.timers dependent
  // $("input[type='file']").iframeFileUpload({blank_pathname: '/my_blank_file.html', autoSubmit: true, onStart: function(el){}, onStop(el){}});
  iframeFileUpload: function(options) {
    return this.each(function(){
      var blank_pathname = options.blank_pathname || '/blank.html';
      var el = $(this);
      var form = el.parents('form');
      var iframe_id = 'iframe_' + form.attr('id');

      if ($('#' + iframe_id).length == 0) {
        var iframe = $("<iframe name='" + iframe_id + "'></iframe>"); // holly ie hack
        iframe.attr('id', iframe_id);
        iframe.css('display', 'none');
        iframe.attr('src', blank_pathname);
        
        $('body').prepend(iframe);
      }
        
      form.attr('target', iframe_id);
      
      if (options.autoSubmit) {
        el.change(function(e){
          form.submit();
            
          (options.onStart)(el);

          jQuery.active++;
          jQuery.event.trigger("ajaxStart");
          jQuery.event.trigger("ajaxSend");

          $(document).everyTime(100, iframe_id, function(i) {
            if ($('#' + iframe_id).contents()[0].location.pathname != blank_pathname) {
              $(document).stopTime(iframe_id);

              --jQuery.active;
              jQuery.event.trigger("ajaxComplete");
              jQuery.event.trigger("ajaxStop");

              iframe.attr('src', blank_pathname);

              $(document).oneTime(10, function(i) {
                (options.onStop)(el);
              });
            }
          });
        });
      }
    });
  }
});