function r_on(i) {
  if (document.images) { 
    if (document[i].src.indexOf("down") < 0) {
      document[i].src = "../images/" + i + "_over.gif"; 
    }
  }
}

function r_off(i) {
  if (document.images) { 
    if (document[i].src.indexOf("down") < 0) {
      document[i].src = "../images/" + i + ".gif"; 
    }
  }
}

function s_on(i) {
  if (document.images) { 
    if (document[i].src.indexOf("down") < 0) {
      document[i].src = "images/" + i + "_over.gif"; 
    }
  }
}

function s_off(i) {
  if (document.images) { 
    if (document[i].src.indexOf("down") < 0) {
      document[i].src = "images/" + i + ".gif"; 
    }
  }
}