What is Difference in render, rerender and renderas attributes of visualforce

What is Difference in render, rerender and renderas attributes of visualforce

rendered– It works like “display” property of CSS. Used to show or hide element.

rerender – After Ajax which component should be refreshed – available on commandlink, commandbutton, actionsupport etc.

renderas – render page as pdf, doc and excel.

<apex:pageBlock rendered="{!ShowpageBlockFlag}">

Public Boolean ShowpageBlockFlag{get;set;}

  Public myControllr (){

   accRec = [select name,id,accountnumber from account limit 1];

   ShowpageBlockFlag = false;

  }

   

  Public void ShowBlockMethod(){

   ShowpageBlockFlag = true;

  }

<apex:pageBlock >

<apex:commandButton value="Refresh" action="{!ShowBlockMethod}" rerender="pgblckID"/>

</apex:pageBlock>

        

<apex:pageBlock id="pgblckID">

      <b>  Output Text   : </b>   <apex:outputText value="{!OutPutString}"/>

</apex:pageBlock>

Public with sharing class myControllr {

  Public string OutPutString{get;set;}

   

  Public myControllr (){

    OutPutString = 'Test value set in Constructor';

  }

   

  Public void ShowBlockMethod(){

   OutPutString = 'value set in methode called by button click' ;

  }

}