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

img[0] = new Image();  img[0].src = "img/b1.gif";
img[1] = new Image();  img[1].src = "img/b1_r.gif";

img[2] = new Image();  img[2].src = "img/b2.gif";
img[3] = new Image();  img[3].src = "img/b2_r.gif";

}

function _in(nam,num) {
if(navigator.appVersion.charAt(0) >= "3") {
document.images[nam].src = img[num].src;
} else { }
}

function _out(nam,num) {
document.images[nam].src = img[num].src;
}