if(navigator.appVersion.charAt(0) >= "3"){
  img = new Array();
  img[0] = new Image; img[0].src = "img/header/detail_on.gif";
  img[1] = new Image; img[1].src = "img/header/feature_on.gif";
  img[2] = new Image; img[2].src = "img/header/technical_on.gif";
  
  img[10] = new Image; img[10].src = "img/header/detail_off.gif";
  img[11] = new Image; img[11].src = "img/header/feature_off.gif";
  img[12] = new Image; img[12].src = "img/header/technical_off.gif";
}
function f_a_mouse(a,b){  //aは下のnameに、bは上の配列に対応
  if(navigator.appVersion.charAt(0) >= "3"){
    document.images[a].src=img[b].src;
  }
}