</apex:pageBlockTable>
      <div id="dis" Class="popup">
          <div Class="divclose">
               <apex:commandLink value="X"  reRender="dis" onclick="hideDiscription()"/>
           </div>
           {!oppdislst}
           <apex:repeat value="{!oppdislst}" var="dis1">
               <apex:outputtext value="{!dis1.Description}" />
           </apex:repeat>
     </div>
  </apex:pageBlock>


 <script>
     function showDiscription(){

              document.getElementById("dis").style.display = "block";

     }
      function hideDiscription(){
              alert('hello close');
             document.getElementById("dis").style.display = "none";
     }
</script>

public class opportunityPageReport{
public list<opportunity> oppLst {get ; set; }

public opportunityPageReport(){
    system.debug('<<<<<<<<<'+oppdislst);
    oppdislst = new list<opportunity>();
    oppLst = new list<opportunity>();
    list<opportunity> oppTemLst = [SELECT Amount, Name, closeDate, LeadSource, StageName, Type , Description FROM Opportunity ];

             for(opportunity opp : oppTemlst){
               if(opp.description !=null){
                 oppLst.add(opp);
               }
         }
     }
 public pageReference Showdiscription(){

        oppdislst = [ select id , Description from opportunity where id =: ApexPages.currentPage().getParameters().get('discriptionid')];
        system.debug('>>>>>>>>>>>>>>>'+oppdislst);
        return null;
   }