ACTION STATUS

<apex:page controller="myPageController" tabStyle="Account">

<apex:form >

<apex:sectionHeader title="My Page" />

<apex:pageBlock title="" id="pageBlock">

<apex:pageBlockButtons location="top">

<apex:inputField id="accountType" value="{!Account.Type}" />

<apex:commandButton value="View" action="{!ViewAccounts}" id="theButton" rerender="pageBlock"></apex:commandButton>

</apex:pageBlockButtons>

<apex:pageMessages ></apex:pageMessages>

<!-- defines a javascript function which calls a Controller's method -->

<apex:actionFunction action="{!ShowSelected}" name="RowMethodCall" rerender="pageBlock" status="status">

<apex:param name="selectedAccount" assignTo="{!selectedAccount}" value=""/>

</apex:actionFunction>

<!-- define a start facet within the actionStatus that has a div with defined id visible to the whole HTML document -->

<apex:actionStatus id="status">

<apex:facet name="start">

<div id="statusTemplate">Working...</div>

</apex:facet>

</apex:actionStatus>

<apex:pageBlockTable value="{!accounts}" var="a" rendered="{!NOT(ISNULL(accounts))}">

<apex:column >

<apex:facet name="header">Account Name</apex:facet>

<apex:outputLink value="/{!a.Id}" target="_blank">{!a.Name}</apex:outputLink>

</apex:column>

<apex:column value="{!a.type}"></apex:column>

<apex:column >

<apex:facet name="header">Action</apex:facet>

<a href="javascript:DoTask('{!a.Id}');">Execute</a>

<div style="display:none" id="{!a.Id}">

Processing {!a.Name} ...

</div>

</apex:column>

</apex:pageBlockTable>

</apex:pageBlock>

<script type="text/javascript">

function DoTask(accountId)

{

var accountStatus = document.getElementById(accountId);

if (accountStatus && accountStatus.innerHTML)

{

document.getElementById('statusTemplate').innerHTML = accountStatus.innerHTML;

}

RowMethodCall(accountId);

}

</script>

</apex:form>

</apex:page>

------------------------------------------------------

public class myPageController {

private Account acc = new Account();

private List<Account> accs;

private string selectedAccount;

public Account getAccount()

{

return acc;

}

public void setAccount(Account a)

{

acc = a;

}

public List<Account> getAccounts()

{

return accs;

}

public string getSelectedAccount()

{

return selectedAccount;

}

public void setSelectedAccount(string value)

{

selectedAccount = value;

}

public PageReference ViewAccounts()

{

if (acc.Type == null)

{

//view a message because validation has failed.

ApexPages.addmessage(newApexPages.message(ApexPages.severity.INFO,'Validation Failed: Select an item fron the dropdown list.'));

return null;

}

string AccountType = acc.Type;

accs = [Select id, name, type from Account where type= :AccountType limit 20];

if (accs == null || accs.size() == 0)

{

ApexPages.addmessage(newApexPages.message(ApexPages.severity.INFO,'No data found to be shown.'));

}

return null;

}

public PageReference ShowSelected()

{

if (selectedAccount != null && selectedAccount != '')

{

for(Account a: accs)

{

if (a.Id == selectedAccount)

{

string Msg = a.Name + ' Account is selected.';

ApexPages.addmessage(newApexPages.message(ApexPages.severity.INFO,Msg ));

}

}

}

return null;

}

}