Expressions in statements must only be executed for their side-effects.

Hey Ladies and Gentle Fish

I am currently trying to do some basic Javascript coding to change levels and am currently running into this issue.

Expressions in statements must only be executed for their side-effects.

My code is shown: (updated with other people ideas, no error now, but not loading different scenes up.)

 #pragma strict
 //Attach to Main Camera
 
 var PageNumber : int = 1;
 var MaxPageNumber : int = 4;
 var MinPageNumber : int = 0;
 
 
 
 function OnGUI () {
     GUI.backgroundColor = Color.red;
     if (GUI.Button(Rect(820,505,80,30),"Next")){
         PageNumber = PageNumber + 1;
         print("click");
         if(PageNumber == MaxPageNumber){
             PageNumber = PageNumber - 1;
         }
         else{
         ChangeLevel();
         }
     }
     if (GUI.Button(Rect(500,505,80,30),"Back")){
         PageNumber = PageNumber - 1;
         if(PageNumber == MinPageNumber){
             PageNumber = PageNumber + 1;
         }
         else{
         ChangeLevel();
         }
     }
 }
 
 function ChangeLevel() {
     if (PageNumber == 1){
         Application.LoadLevel ("Page 2");
     }
     else if (PageNumber == 2){
         Application.LoadLevel ("Page 3");
     }
     else{
         Application.LoadLevel ("Page 4");
     }
 }