Difficulty in Understanding Slideshow script
- by shining star
I have taken slide show script from net. But There some functions i cannot understand
here is script
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd"
>
<html lang="en">
<head>
<title></title>
<script>
var interval = 1500;
var random_display = 0;
var imageDir = "my_images/";
var imageNum = 0;
imageArray = new Array();
imageArray[imageNum++] = new imageItem(imageDir + "01.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "02.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "03.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "04.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "05.jpg");
var totalImages = imageArray.length;
function imageItem(image_location) {
this.image_item = new Image();
this.image_item.src = image_location;
return this.image_item.src;
}
function get_ImageItemLocation(imageObj) {
return(imageObj.image_item.src)
}
alert(imageArray[imageNum].image_item.src);
function randNum(x, y) {
var range = y - x + 1;
return Math.floor(Math.random() * range) + x;
}
function getNextImage() {
if (random_display) {
imageNum = randNum(0, totalImages-1);
}
else {
imageNum = (imageNum+1) % totalImages;
}
var new_image = get_ImageItemLocation(imageArray[imageNum]);
//alert(new_image)
return(new_image);
}
function getPrevImage() {
imageNum = (imageNum-1) % totalImages;
var new_image = get_ImageItemLocation(imageArray[imageNum]);
return(new_image);
}
function prevImage(place) {
var new_image = getPrevImage();
document[place].src = new_image;
}
function switchImage(place) {
var new_image = getNextImage();
document[place].src = new_image;
var recur_call = "switchImage('"+place+"')";
timerID = setTimeout(recur_call, interval);
}
</script>
</head>
<body onLoad="switchImage('slideImg')">
<img name="slideImg" src="27.jpg" width=500 height=375 border=0>
<a href="#" onClick="switchImage('slideImg')">play slide show</a>
<a href="#" onClick="clearTimeout(timerID)"> pause</a>
<a href="#" onClick="prevImage('slideImg'); clearTimeout(timerID)"> previous</a>
<a href="#" onClick="switchImage('slideImg'); clearTimeout(timerID)">next </a>
</body>
</html>
here exactly i dont know what does acctually function of
get_ImageItemLocation(imageObj)
and
imageItem(image_location)
what does these two functions seperately?
Thanks in advance for attention
