NewImg = new Array (
"../images_f/f_tavdivo1.jpg",
"../images_f/f_tavdivo2.jpg",
"../images_f/f_tavdivo3.jpg"
);
var ImgNum = 0;
var ImgLength = NewImg.length - 1;
var delay = 3000;

var lock = false;
var run;
function chgImg(direction) {
if (document.images) {
ImgNum = ImgNum + direction;
if (ImgNum > ImgLength) {
ImgNum = 0;
}
if (ImgNum < 0) {
ImgNum = ImgLength;
}
document.slideshow.src = NewImg[ImgNum];
   }
}
function auto() {
if (lock == true) {
lock = false;
window.clearInterval(run);
}
else if (lock == false) {
lock = true;
run = setInterval("chgImg(1)", delay);
   }
}

// img src="" name="slideshow"