function getFo(Fo){
  switch(Fo){
  case 1: 
     document.images["RU_IMG"].src = "/main/images/ru3_centr.gif";
     break;
  case 2: 
     document.images["RU_IMG"].src = "/main/images/ru3_sevzap.gif";
     break;
  case 3: 
     document.images["RU_IMG"].src = "/main/images/ru3_privol.gif";
     break;
  case 4: 
     document.images["RU_IMG"].src = "/main/images/ru3_uzhny.gif";
     break;
  case 5: 
     document.images["RU_IMG"].src = "/main/images/ru3_sevkavkz.gif";
     break;
  case 6: 
     document.images["RU_IMG"].src = "/main/images/ru3_ural.gif";
     break;
  case 7: 
     document.images["RU_IMG"].src = "/main/images/ru3_sib.gif";
     break;
  case 8: 
     document.images["RU_IMG"].src = "/main/images/ru3_dalvost.gif";
     break;
  default:
     document.images["RU_IMG"].src = "/main/images/ru2.gif";
  } //switch
}