var updater = Class.create({  
    initialize: function(divToUpdate, interval, file) {  
         this.divToUpdate = divToUpdate;  
         this.interval = interval;  
         this.file = file;  
        new PeriodicalExecuter(this.getUpdate.bind(this), this.interval);  
    },  
       
     getUpdate: function() {  
         var div = this.divToUpdate;  
         var interval = this.interval;  
         var file = this.file;              
         var oOptions = {  
             method: "POST",  
             asynchronous: true,  
             parameters: "intervalPeriod="+interval,  
             onComplete: function (oXHR, Json) {  
                 $(div).innerHTML = oXHR.responseText;  
             }  
         };  
         var oRequest = new Ajax.Updater(div, file, oOptions);  
     }  
 });