Apex Coding on Updating Records Using VisualForce Page with Controller.....

Page:
----
<apex:page StandardController="Event" extensions="eventcontroller">
  <script>
    function confirmCancel()
    {
        var isCancel = confirm("Are you sure you wish to cancel?");
        if (isCancel) return true;
        return false;
    }
   var newWin=null;
   function fillFields(oSel)
    {
         var oForm = oSel.parent;
         //alert(oSel.options[oSel.selectedIndex].value);
         switch (oSel.options[oSel.selectedIndex].value)
         {
            case "Yes":
                // document.getElementById('j_id0:parent:j_id3:choice').disabled=true;
                 document.getElementById('test1').style.display='none';
                 document.getElementById('j_id0:parent:j_id30:choice').style.display='none';
                 break;
            case "No":
                 document.getElementById('test1').style.display='block';
                 document.getElementById('test2').style.display='block';
                document.getElementById('j_id0:parent:j_id30:choice').style.display='block';
                 break;
               
                 default :
                 //document.getElementById('j_id0:parent:j_id30:choice').disabled=true;
                 document.getElementById('test1').style.display='none';
                 document.getElementById('j_id0:parent:j_id30:choice').style.display='none';
                }
    }
       
   
    </script>
  <apex:sectionHeader title="Complete Meeting Edit" subtitle="Complete Meeting"/>
 <apex:form id="parent">
 <apex:pageMessages > </apex:pageMessages>
    <apex:pageBlock title="Complete Meeting Edit" mode="edit">
  <apex:pageBlockButtons >
     <apex:commandButton action="{!save1}" value="Save"/>
     <apex:commandButton action="{!cancel}" value="Cancel" onclick="return confirmCancel()" immediate="true"/>
  </apex:pageBlockButtons>
 
  <table  style="padding-left:200px">
       <tr>
          <td>&nbsp;
          </td>
      </tr>
       <tr>
           <td align="right"><b>Meeting is Valid:</b>
           </td>
           <td align="left">
               <apex:inputField value="{!events.Attend__c}" required="true" onchange="fillFields(this)"/>
           </td>
       </tr>
       <tr>
           <td align="right"><p id="test1" style="display:none" ><b>Reason for Failure:</b></P>
           </td>
           <td  id="test2" align="left">
                 <apex:inputField value="{!events.Reason__c}" required="true" id="choice" style="display:none"/>
           </td>
       </tr>        
  </table>
 </apex:pageBlock>
  </apex:form>
</apex:page>


Controller:
============
public class eventcontroller
{
 
    public eventcontroller(ApexPages.StandardController controller)
    {
    }  
   Event events;
   public Event getevents()
   {
        if(events== null)
            events = new Event();
        return events;
    }
    public PageReference save1()
    {
     
      Event e = new Event();
      String eventid= System.currentPageReference().getParameters().get('eid');
      system.debug('Event:'+eventid);
      e = [Select e.Attend__c, e.Id, e.Reason__c from Event e  where e.id=:eventid];
     
        system.debug('Event details:'+e);
        e.Attend__c=events.Attend__c;
        e.Reason__c=events.Reason__c;
        e.Meeting_Completed__c =true;
        update e;
        //ApexPages.addmessage(new ApexPages.message(ApexPages.severity.INFO,'Record(s) have been Updated Successfully.Please Refresh Your Account Record to see the imported data'));
        PageReference redirecturl = new PageReference('https://ap1.salesforce.com/'+eventid);
        return redirecturl;
        //return null;
    }

}