Hi All,

   I have this piece of code here, given below:

     <apex:pageBlock id="tEntryWeekSelectionPageBlock">
         <apex:actionRegion >  
         <apex:pageBlockSection id="selectedWeek" title="Project List for {!$User.FirstName} {!$User.LastName}" columns="2" collapsible="true">
              <apex:pageBlockSectionItem id="selectedWeek">
              <apex:outputLabel for="selectedWeek">Week Beginning</apex:outputLabel>
                  <apex:panelGroup >
                  <apex:selectList value="{!selectedWeek}" multiselect="false" size="1">
                      <apex:selectOptions value="{!Weeks}"/>
                  </apex:selectList>  
                 </apex:panelGroup>
              </apex:pageBlockSectionItem>
              <apex:commandButton value="Go"  action="{!setWeek}" rerender="timeEntryBlock, messageBlock"/>
        </apex:pageBlockSection>
        </apex:actionRegion>  
        </apex:pageBlock>

Now the action="{!setWeek}" is working perfectly on click of the button. But now I want to perform the same action on change of value in my apex:selectList value="{!selectedWeek}", when I make the given change to my code , it throws an error.

  <apex:selectList value="{!selectedWeek}" multiselect="false" size="1" onchange="!{setWeek}">

Can anyone please help  me with this?