if(navigator.appVersion.charAt(0) >= 3) {
var img = new Array();

img[1] = new Image();  img[1].src="img/btn01_on.jpg"; 
img[2] = new Image();  img[2].src="img/btn01_off.jpg"; 
img[3] = new Image();  img[3].src="img/btn02_on.jpg"; 
img[4] = new Image();  img[4].src="img/btn02_off.jpg"; 
img[5] = new Image();  img[5].src="img/btn03_on.jpg"; 
img[6] = new Image();  img[6].src="img/btn03_off.jpg"; 
img[7] = new Image();  img[7].src="img/btn04_on.jpg"; 
img[8] = new Image();  img[8].src="img/btn04_off.jpg"; 
img[9] = new Image();  img[9].src="img/btn05_on.jpg"; 
img[10] = new Image();  img[10].src="img/btn05_off.jpg"; 
}
function change_image(nam,num) {
  if(navigator.appVersion.charAt(0) >= 3) {
    document.images[nam].src = img[num].src;
  }
}