jquery.poller.js

$.extend({
  poller: function(originalOptions){
    var applyRepoll = function(callback){
      return function(){
        if(typeof callback === 'function'){
          callback.apply(originalOptions, arguments);
        }
        $.poller(originalOptions);
      };
    };
    
    var extendedOptions = $.extend({}, originalOptions, {
      async:    true,   /* If set to non-async, browser shows page as "Loading.."*/
      timeout:  30000,  /* Timeout in ms */
      cache:    false,
      success:  applyRepoll(originalOptions.success),
      error:    applyRepoll(originalOptions.error)
    });
    
    return $.ajax(extendedOptions);
  }
});