apex:actionRegion

1<!-- For this example to render properly, you must associate the Visualforce page 
2with a valid opportunity record in the URL. 
3For example, if 001D000000IRt53 is the opportunity ID, the resulting URL should be: 
4https://Salesforce_instance/apex/myPage?id=001D000000IRt53
5See the Visualforce Developer's Guide Quick Start Tutorial for more information. -->
6
7<apex:page standardController="Opportunity">
8  <apex:form >
9    <apex:pageBlock title="Edit Opportunity" id="thePageBlock" mode="edit">
10   
11      <apex:pageBlockButtons >
12        <apex:commandButton value="Save" action="{!save}"/>
13        <apex:commandButton value="Cancel" action="{!cancel}"/>               
14      </apex:pageBlockButtons>
15
16    <apex:pageBlockSection columns="1">
17      <apex:inputField value="{!opportunity.name}"/>
18      <apex:pageBlockSectionItem>
19      <apex:outputLabel value="{!$ObjectType.opportunity.fields.stageName.label}" 
20                        for="stage"/>
21      <!-- 
22           Without the actionregion, selecting a stage from the picklist would cause 
23           a validation error if you hadn't already entered data in the required name 
24           and close date fields.  It would also update the timestamp.
25      -->
26      <apex:actionRegion>
27        <apex:inputField value="{!opportunity.stageName}" id="stage">
28          <apex:actionSupport event="onchange" rerender="thePageBlock"
29                              status="status"/>
30          </apex:inputField>
31          </apex:actionRegion>
32      </apex:pageBlockSectionItem>
33        <apex:inputfield value="{!opportunity.closedate}"/>
34        {!text(now())}
35        </apex:pageBlockSection>
36
37      </apex:pageBlock>
38    </apex:form>
39</apex:page>