apex:actionStatus

1<!--  Page: -->
2			
3<apex:page controller="exampleCon">
4    <apex:form>
5        <apex:outputText value="Watch this counter: {!count}" id="counter"/>
6        <apex:actionStatus startText=" (incrementing...)"
7            stopText=" (done)" id="counterStatus"/>
8        <apex:actionPoller action="{!incrementCounter}" rerender="counter"
9            status="counterStatus" interval="15"/>
10    </apex:form>
11</apex:page>
12			
13/*** Controller: ***/
14			
15public class exampleCon {
16    Integer count = 0;
17                        
18    public PageReference incrementCounter() {
19            count++;
20            return null;
21    }
22                        
23    public Integer getCount() {
24        return count;
25    }
26}