动态图形转换带Cookie

提示：看下面的图形，会自动变换，共有三张循环，每张图片的链接地址都不同。并通过Cookie记住某图片是否已显示。

1.将下面的代码放到<body>或<head>内

function getCookieVal (offset) {
  var endstr = document.cookie.indexOf (";", offset);
  if (endstr == -1)
    endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset, endstr));  }

function FixCookieDate (date) {
  var base = new Date(0);
  var skew = base.getTime(); // dawn of (Unix) time - should be 0
  if (skew > 0)  // Except on the Mac - ahead of its time
    date.setTime (date.getTime() - skew);  }

function GetCookie (name) {
  var arg = name + "=";
  var alen = arg.length;
  var clen = document.cookie.length;
  var i = 0;
  while (i < clen) {
    var j = i + alen;
    if (document.cookie.substring(i, j) == arg)
      return getCookieVal (j);
	i = document.cookie.indexOf(" ", i) + 1;
    if (i == 0) break; }
  return null;   }

//  assign expiration date variable for cookie

var expdate = new Date ();
FixCookieDate(expdate); 
expdate.setTime(expdate.getTime() + (5 * 60 * 1000)) // 5 minutes

//  initialize countimg variable to track images
countimg = (GetCookie("countimg") != null) ? (GetCookie("countimg")-1) : -1
countimg = (countimg <-1) ? -1 : countimg
IMGArray = new Array(3)

if (document.images) {
	IMGArray[0] = new Image(205,56)
	IMGArray[1] = new Image(205,56)
	IMGArray[2] = new Image(205,56) 	 }

//	Old browsers get an array of empty strings

else {
	IMGArray[0] = ""
	IMGArray[1] = ""
	IMGArray[2] = "" 						}

IMGArray[0].src = "http://www.ie-zone.com/banners/a01.gif"
IMGArray[0].URL = "http://www.163.net"
IMGArray[1].src = "http://www.ie-zone.com/banners/a02.gif"
IMGArray[1].URL = "http://www.163.com"
IMGArray[2].src = "http://www.ie-zone.com/banners/a03.gif"
IMGArray[2].URL = "http://www.gznet.com"

function updateIM(countimg) { return countimg; }

//  functions for onMouseOver, onMouseOut, onClick event handlers

function Overhref2() { updateIM(countimg)
	if (IMGArray[countimg] != null ) { 
	window.status = IMGArray[countimg].URL; return true; }}

function Outhref2() { window.status = ""; return true; }

function clickhref2() { updateIM(countimg)
	if (IMGArray[countimg] != null ) { 
	location = IMGArray[countimg].URL }}

//  Image swapping function

function showIMAGE() { updateIM(countimg++)

if (document.images) {

//	Make sure countimg does'nt get too big

if ( countimg > IMGArray.length - 1 ) { countimg = IMGArray.length - IMGArray.length }

document.images.banner.src = IMGArray[countimg].src 
	exbannerID = setTimeout("showIMAGE()",2500) }}

function setIt2() { updateIM(countimg)
	document.cookie = "countimg=" + countimg + "; expires=" + expdate.toGMTString()  }

//  get cookie countimg onblur, onload

function getIt2() { 
	countimg = (GetCookie("countimg") != null) ? (GetCookie("countimg")) : 0
	updateIM(countimg)
	if (exbannerID != null) { clearTimeout(exbannerID); showIMAGE() }}

function initCOOKIES() {

window.onunload = setIt2
window.onfocus = getIt2
window.onblur = setIt2 	}

function initBANNER() {
	
	showIMAGE() 
	cookieID = setTimeout("initCOOKIES()",1000) }

window.onload = initBANNER

// -->
</script>

2.修改Script中的图片路径与连接网址
IMGArray[0].src = "http://www.ie-zone.com/banners/a01.gif"
IMGArray[0].URL = "http://www.163.net"
IMGArray[1].src = "http://www.ie-zone.com/banners/a02.gif"
IMGArray[1].URL = "http://www.163.com"
IMGArray[2].src = "http://www.ie-zone.com/banners/a03.gif"
IMGArray[2].URL = "http://www.gznet.com"

3. 在需要加入变换效果的地方加上
<a href="" onClick="clickhref2()" onMouseOver="Overhref2();return true;" onMouseOut="Outhref2;return true;"><img src="" name="banner" border="0" ></a>