//resolucao de ecra
switch(screen.width) {
              
  case 800: IrParaURL('index800.php'); 
             break;
                         
  case 1024: IrParaURL('index1024.php'); 
              break;
              
  case 1152: IrParaURL('index1152.php'); 
              break;
              
  case 1280: IrParaURL('index1280.php'); 
              break;
              
  case 1360: IrParaURL('index1300.php'); 
             break;
  
  case 1366: IrParaURL('index1366.php'); 
            break;
            
  case 1400: IrParaURL('index1400.php'); 
            break;
            
  case 1440: IrParaURL('index1440.php'); 
             break;
  
  case 1600: IrParaURL('index1600.php'); 
             break;
             
  case 1680: IrParaURL('index1680.php'); 
             break;
              
  case 1920: IrParaURL('index1920.php'); 
              break;
              
  default : IrParaURL('index1280.php'); 
            break;
}

function IrParaURL(url) {
 location.href=url;
}