<apex:page standardController="Employee__c" extensions="Chbox_ShowHide_Controller">

  <apex:form >
      <apex:pageBlock id="cpBlock" rendered="true" >
      <apex:pageBlockButtons >
          <apex:commandButton value="save" action="{!save}"/>
           <apex:commandButton value="Cancel" action="{!cancel}"/>
      </apex:pageBlockButtons>
      
          <apex:pageBlockSection title="Personal Details" id="Block">
              <apex:inputField value="{!employeeRecord.First_Name__c}"/>
              <apex:inputField value="{!employeeRecord.Last_Name__c}"/>
              <apex:inputField value="{!employeeRecord.DOB__c}"/>
              <apex:inputField value="{!employeeRecord.Email__c}"/>
              <apex:inputField value="{!employeeRecord.Address__c}"/>
          </apex:pageBlockSection>
               <apex:outputText value="Employed"/>
          <apex:inputCheckbox id="val" value="{!optSelected}" label="Employed"> 
                   <apex:actionSupport event="onchange" reRender="cpBlock" action="{!display}"/>
                </apex:inputCheckbox> 
         
                
            <apex:outputPanel id="r" rendered="{!optSelected }">
            <apex:pageBlockSection title="Employment Details" rendered="{!if(ShowHide==true,true,false)}">
              <apex:inputField value="{!employeeRecord.Company_Name__c}"/>
              <apex:inputField value="{!employeeRecord.Company_Address__c}"/>
              <apex:inputField value="{!employeeRecord.Date_of_Joining__c}"/>
              <apex:inputField value="{!employeeRecord.Notice_Period__c}"/>
              <apex:inputField value="{!employeeRecord.Designation__c}"/>
              <apex:inputField value="{!employeeRecord.Department__c}"/>
          </apex:pageBlockSection>
          </apex:outputPanel>
         
          <apex:outputPanel id="re">
           {!showHide}
          <apex:pageBlockSection title="Skill Sets" rendered="{!if(ShowHide==false,true,false)}">
              <apex:inputField value="{!employeeRecord.Graduation__c}"/>
              <apex:inputField value="{!employeeRecord.Post_Graduation__c}"/>
              <apex:inputField value="{!employeeRecord.University__c}"/>
              <apex:inputField value="{!employeeRecord.College_Name__c}"/>
              <apex:inputField value="{!employeeRecord.Programming_Languages__c}"/>
          </apex:pageBlockSection>
          </apex:outputPanel>
      </apex:pageBlock>
  </apex:form>
</apex:page>

public class Chbox_ShowHide_Controller 
{
    public Boolean ShowHide{get;set;}
    public Employee__c employeeRecord {get;set;}
    //del it
  public String optSelected {get;set;}
  public List<System.SelectOption> ChkValues{
      get{
		List<SelectOption> resList = new List<SelectOption>();
        resList.add(new SelectOption('Option1', 'Personal details'));
        resList.add(new SelectOption('Option2', 'Proffessional Details'));
        return resList;
	  }
  }
  public Boolean renderName1{
	get{return optSelected == 'Option1'; }
  }
public Boolean renderName2{ 
	get{return optSelected == 'Option1'; }
}
  
  public void display(){
      ShowHide=true;
  }
 
       
   public Chbox_ShowHide_Controller(ApexPages.StandardController controller){
		employeeRecord = new Employee__c();
		id recordId = ApexPages.currentPage().getParameters().get('id');
		if(recordId != null){
				for(Employee__c emp : [select First_Name__c, Last_Name__c, DOB__c, Email__c, Address__c, Company_Name__c,
										Company_Address__c, Date_of_Joining__c, Notice_Period__c, Designation__c, Department__c,
										Graduation__c, Post_Graduation__c, University__c, College_Name__c, Programming_Languages__c from Employee__c
										where id=: employeeRecord]){
							employeeRecord = emp;
						
				}
				
		}
        
   }
   public Pagereference recordSave(){
		
		try{
		    upsert employeeRecord;
			// Send the user to the detail page for the Employee__c record.
	        PageReference employeePage = new ApexPages.StandardController(employeeRecord).view();
	        employeePage.setRedirect(true);
         return employeePage;
        }
		catch(exception ex){
				system.debug(':::::::;;Exception in class Chbox_ShowHide_Controller:::::::::::::::');
				
		}
		return null;
   }
}