我正在更新客户的网站，使其包含alt标签，以使其网站符合ADA规范。我有几页使用https://lokeshdhakar.com/projects/lightbox2中的Lightbox2。我将ALT属性添加到了数组中，但是没有在脚本中调用它，因此没有添加。
<a href="images/slide-show/at-the-beach-boys.jpg" title="An easy walk to fun at Long Sands Beach." alt="Small boys use sand toys on Long Sands Beach." rel="lightbox[Overview]"><img src="images/slide-show/at-the-beach-boys-th.jpg" alt="Small boys use sand toys on Long Sands Beach." width="256" height="176" /></a>
我已尝试编辑lightbox.js以包括alt标签调用，但未成功。
lightbox.js的内容
// -----------------------------------------------------------------------------------
//
// Lightbox v2.03.3
// by Lokesh Dhakar - http://www.huddletogether.com
// 5/21/06
//
// For more information on this script, visit:
// http://huddletogether.com/projects/lightbox2/
//
// Licensed under the Creative Commons Attribution 2.5 License - http://creativecommons.org/licenses/by/2.5/
//
// Credit also due to those who have helped, inspired, and made their code available to the public.
// Including: Scott Upton(uptonic.com), Peter-Paul Koch(quirksmode.com), Thomas Fuchs(mir.aculo.us), and others.
//
//
// -----------------------------------------------------------------------------------
/*
Table of Contents
-----------------
Configuration
Global Variables
Extending Built-in Objects
- Object.extend(Element)
- Array.prototype.removeDuplicates()
- Array.prototype.empty()
Lightbox Class Declaration
- initialize()
- updateImageList()
- start()
- changeImage()
- resizeImageContainer()
- showImage()
- updateDetails()
- updateNav()
- enableKeyboardNav()
- disableKeyboardNav()
- keyboardAction()
- preloadNeighborImages()
- end()
Miscellaneous Functions
- getPageScroll()
- getPageSize()
- getKey()
- listenKey()
- showSelectBoxes()
- hideSelectBoxes()
- showFlash()
- hideFlash()
- pause()
- initLightbox()
Function Calls
- addLoadEvent(initLightbox)
*/
// -----------------------------------------------------------------------------------
//
// Configuration
//
var fileLoadingImage = "../lightbox_assets/images/loading.gif";
var fileBottomNavCloseImage = "../lightbox_assets/images/closelabel.gif";
var overlayOpacity = 0.8; // controls transparency of shadow overlay
var animate = true; // toggles resizing animations
var resizeSpeed = 7; // controls the speed of the image resizing animations (1=slowest and 10=fastest)
var borderSize = 10; //if you adjust the padding in the CSS, you will need to update this variable
// -----------------------------------------------------------------------------------
//
// Global Variables
//
var imageArray = new Array;
var activeImage;
if(animate == true){
overlayDuration = 0.2; // shadow fade in/out duration
if(resizeSpeed > 10){ resizeSpeed = 10;}
if(resizeSpeed < 1){ resizeSpeed = 1;}
resizeDuration = (11 - resizeSpeed) * 0.15;
} else {
overlayDuration = 0;
resizeDuration = 0;
}
// -----------------------------------------------------------------------------------
//
// Additional methods for Element added by SU, Couloir
// - further additions by Lokesh Dhakar (huddletogether.com)
//
Object.extend(Element, {
getWidth: function(element) {
element = $(element);
return element.offsetWidth;
},
setWidth: function(element,w) {
element = $(element);
element.style.width = w +"px";
},
setHeight: function(element,h) {
element = $(element);
element.style.height = h +"px";
},
setTop: function(element,t) {
element = $(element);
element.style.top = t +"px";
},
setLeft: function(element,l) {
element = $(element);
element.style.left = l +"px";
},
setSrc: function(element,src) {
element = $(element);
element.src = src;
},
setHref: function(element,href) {
element = $(element);
element.href = href;
},
setInnerHTML: function(element,content) {
element = $(element);
element.innerHTML = content;
}
});
// -----------------------------------------------------------------------------------
//
// Extending built-in Array object
// - array.removeDuplicates()
// - array.empty()
//
Array.prototype.removeDuplicates = function () {
for(i = 0; i < this.length; i++){
for(j = this.length-1; j>i; j--){
if(this[i][0] == this[j][0]){
this.splice(j,1);
}
}
}
}
// -----------------------------------------------------------------------------------
Array.prototype.empty = function () {
for(i = 0; i <= this.length; i++){
this.shift();
}
}
// -----------------------------------------------------------------------------------
//
// Lightbox Class Declaration
// - initialize()
// - start()
// - changeImage()
// - resizeImageContainer()
// - showImage()
// - updateDetails()
// - updateNav()
// - enableKeyboardNav()
// - disableKeyboardNav()
// - keyboardNavAction()
// - preloadNeighborImages()
// - end()
//
// Structuring of code inspired by Scott Upton (http://www.uptonic.com/)
//
var Lightbox = Class.create();
Lightbox.prototype = {
// initialize()
// Constructor runs on completion of the DOM loading. Calls updateImageList and then
// the function inserts html at the bottom of the page which is used to display the shadow
// overlay and the image container.
//
initialize: function() {
this.updateImageList();
// Code inserts html at the bottom of the page that looks similar to this:
//
// <div id="overlay"></div>
// <div id="lightbox">
// <div id="outerImageContainer">
// <div id="imageContainer">
// <img id="lightboxImage" alt="container for enlarged images">
// <div style="" id="hoverNav">
// <a href="#" id="prevLink"></a>
// <a href="#" id="nextLink"></a>
// </div>
// <div id="loading">
// <a href="#" id="loadingLink">
// <img src="images/loading.gif" alt"Waiting to load">
// </a>
// </div>
// </div>
// </div>
// <div id="imageDataContainer">
// <div id="imageData">
// <div id="imageDetails">
// <span id="caption"></span>
// <span id="numberDisplay"></span>
// </div>
// <div id="bottomNav">
// <a href="#" id="bottomNavClose">
// <img src="../images/close.gif" alt="X graphic to close lightbox">
// </a>
// </div>
// </div>
// </div>
// </div>
var objBody = document.getElementsByTagName("body").item(0);
var objOverlay = document.createElement("div");
objOverlay.setAttribute('id','overlay');
objOverlay.style.display = 'none';
objOverlay.onclick = function() { myLightbox.end(); }
objBody.appendChild(objOverlay);
var objLightbox = document.createElement("div");
objLightbox.setAttribute('id','lightbox');
objLightbox.style.display = 'none';
objLightbox.onclick = function(e) { // close Lightbox is user clicks shadow overlay
if (!e) var e = window.event;
var clickObj = Event.element(e).id;
if ( clickObj == 'lightbox') {
myLightbox.end();
}
};
objBody.appendChild(objLightbox);
var objOuterImageContainer = document.createElement("div");
objOuterImageContainer.setAttribute('id','outerImageContainer');
objLightbox.appendChild(objOuterImageContainer);
// When Lightbox starts it will resize itself from 250 by 250 to the current image dimension.
// If animations are turned off, it will be hidden as to prevent a flicker of a
// white 250 by 250 box.
if(animate){
Element.setWidth('outerImageContainer', 250);
Element.setHeight('outerImageContainer', 250);
} else {
Element.setWidth('outerImageContainer', 1);
Element.setHeight('outerImageContainer', 1);
}
var objImageContainer = document.createElement("div");
objImageContainer.setAttribute('id','imageContainer');
objOuterImageContainer.appendChild(objImageContainer);
var objLightboxImage = document.createElement("img");
objLightboxImage.setAttribute('id','lightboxImage');
objImageContainer.appendChild(objLightboxImage);
var objHoverNav = document.createElement("div");
objHoverNav.setAttribute('id','hoverNav');
objImageContainer.appendChild(objHoverNav);
var objPrevLink = document.createElement("a");
objPrevLink.setAttribute('id','prevLink');
objPrevLink.setAttribute('href','#');
objHoverNav.appendChild(objPrevLink);
var objNextLink = document.createElement("a");
objNextLink.setAttribute('id','nextLink');
objNextLink.setAttribute('href','#');
objHoverNav.appendChild(objNextLink);
var objLoading = document.createElement("div");
objLoading.setAttribute('id','loading');
objImageContainer.appendChild(objLoading);
var objLoadingLink = document.createElement("a");
objLoadingLink.setAttribute('id','loadingLink');
objLoadingLink.setAttribute('href','#');
objLoadingLink.onclick = function() { myLightbox.end(); return false; }
objLoading.appendChild(objLoadingLink);
var objLoadingImage = document.createElement("img");
objLoadingImage.setAttribute('src', fileLoadingImage);
objLoadingImage.setAttribute('alt', 'Image Loading icon');
objLoadingLink.appendChild(objLoadingImage);
var objImageDataContainer = document.createElement("div");
objImageDataContainer.setAttribute('id','imageDataContainer');
objLightbox.appendChild(objImageDataContainer);
var objImageData = document.createElement("div");
objImageData.setAttribute('id','imageData');
objImageDataContainer.appendChild(objImageData);
var objImageDetails = document.createElement("div");
objImageDetails.setAttribute('id','imageDetails');
objImageData.appendChild(objImageDetails);
var objCaption = document.createElement("span");
objCaption.setAttribute('id','caption');
objImageDetails.appendChild(objCaption);
var objNumberDisplay = document.createElement("span");
objNumberDisplay.setAttribute('id','numberDisplay');
objImageDetails.appendChild(objNumberDisplay);
var objBottomNav = document.createElement("div");
objBottomNav.setAttribute('id','bottomNav');
objImageData.appendChild(objBottomNav);
var objBottomNavCloseLink = document.createElement("a");
objBottomNavCloseLink.setAttribute('id','bottomNavClose');
objBottomNavCloseLink.setAttribute('href','#');
objBottomNavCloseLink.onclick = function() { myLightbox.end(); return false; }
objBottomNav.appendChild(objBottomNavCloseLink);
var objBottomNavCloseImage = document.createElement("img");
objBottomNavCloseImage.setAttribute('src', fileBottomNavCloseImage);
objBottomNavCloseImage.setAttribute('alt', 'CLOSE X');
objBottomNavCloseLink.appendChild(objBottomNavCloseImage);
},
//
// updateImageList()
// Loops through anchor tags looking for 'lightbox' references and applies onclick
// events to appropriate links. You can rerun after dynamically adding images w/ajax.
//
updateImageList: function() {
if (!document.getElementsByTagName){ return; }
var anchors = document.getElementsByTagName('a');
var areas = document.getElementsByTagName('area');
// loop through all anchor tags
for (var i=0; i<anchors.length; i++){
var anchor = anchors[i];
var relAttribute = String(anchor.getAttribute('rel'));
// use the string.match() method to catch 'lightbox' references in the rel attribute
if (anchor.getAttribute('href') && (relAttribute.toLowerCase().match('lightbox'))){
anchor.onclick = function () {myLightbox.start(this); return false;}
}
}
// loop through all area tags
// todo: combine anchor & area tag loops
for (var i=0; i< areas.length; i++){
var area = areas[i];
var relAttribute = String(area.getAttribute('rel'));
// use the string.match() method to catch 'lightbox' references in the rel attribute
if (area.getAttribute('href') && (relAttribute.toLowerCase().match('lightbox'))){
area.onclick = function () {myLightbox.start(this); return false;}
}
}
},
//
// start()
// Display overlay and lightbox. If image is part of a set, add siblings to imageArray.
//
start: function(imageLink) {
hideSelectBoxes();
hideFlash();
// stretch overlay to fill page and fade in
var arrayPageSize = getPageSize();
Element.setWidth('overlay', arrayPageSize[0]);
Element.setHeight('overlay', arrayPageSize[1]);
new Effect.Appear('overlay', { duration: overlayDuration, from: 0.0, to: overlayOpacity });
imageArray = [];
imageNum = 0;
if (!document.getElementsByTagName){ return; }
var anchors = document.getElementsByTagName( imageLink.tagName);
// if image is NOT part of a set..
if((imageLink.getAttribute('rel') == 'lightbox')){
// add single image to imageArray
imageArray.push(new Array(imageLink.getAttribute('href'), imageLink.getAttribute('title')));
} else {
// if image is part of a set..
// loop through anchors, find other images in set, and add them to imageArray
for (var i=0; i<anchors.length; i++){
var anchor = anchors[i];
if (anchor.getAttribute('href') && (anchor.getAttribute('rel') == imageLink.getAttribute('rel'))){
imageArray.push(new Array(anchor.getAttribute('href'), anchor.getAttribute('title')));
}
}
imageArray.removeDuplicates();
while(imageArray[imageNum][0] != imageLink.getAttribute('href')) { imageNum++;}
}
// calculate top and left offset for the lightbox
var arrayPageScroll = getPageScroll();
var lightboxTop = arrayPageScroll[1] + (arrayPageSize[3] / 10);
var lightboxLeft = arrayPageScroll[0];
Element.setTop('lightbox', lightboxTop);
Element.setLeft('lightbox', lightboxLeft);
Element.show('lightbox');
this.changeImage(imageNum);
},
//
// changeImage()
// Hide most elements and preload image in preparation for resizing image container.
//
changeImage: function(imageNum) {
activeImage = imageNum; // update global var
// hide elements during transition
if(animate){ Element.show('loading');}
Element.hide('lightboxImage');
Element.hide('alt');
Element.hide('hoverNav');
Element.hide('prevLink');
Element.hide('nextLink');
Element.hide('imageDataContainer');
Element.hide('numberDisplay');
imgPreloader = new Image();
// once image is preloaded, resize image container
imgPreloader.onload=function(){
Element.setSrc('lightboxImage', imageArray[activeImage][0]);
myLightbox.resizeImageContainer(imgPreloader.width, imgPreloader.height);
imgPreloader.onload=function(){}; // clear onLoad, IE behaves irratically with animated gifs otherwise
}
imgPreloader.src = imageArray[activeImage][0];
},
//
// resizeImageContainer()
//
resizeImageContainer: function( imgWidth, imgHeight) {
// get curren width and height
this.widthCurrent = Element.getWidth('outerImageContainer');
this.heightCurrent = Element.getHeight('outerImageContainer');
// get new width and height
var widthNew = (imgWidth + (borderSize * 2));
var heightNew = (imgHeight + (borderSize * 2));
// scalars based on change from old to new
this.xScale = ( widthNew / this.widthCurrent) * 100;
this.yScale = ( heightNew / this.heightCurrent) * 100;
// calculate size difference between new and old image, and resize if necessary
wDiff = this.widthCurrent - widthNew;
hDiff = this.heightCurrent - heightNew;
if(!( hDiff == 0)){ new Effect.Scale('outerImageContainer', this.yScale, {scaleX: false, duration: resizeDuration, queue: 'front'}); }
if(!( wDiff == 0)){ new Effect.Scale('outerImageContainer', this.xScale, {scaleY: false, delay: resizeDuration, duration: resizeDuration}); }
// if new and old image are same size and no scaling transition is necessary,
// do a quick pause to prevent image flicker.
if((hDiff == 0) && (wDiff == 0)){
if (navigator.appVersion.indexOf("MSIE")!=-1){ pause(250); } else { pause(100);}
}
Element.setHeight('prevLink', imgHeight);
Element.setHeight('nextLink', imgHeight);
Element.setWidth( 'imageDataContainer', widthNew);
this.showImage();
},
//
// showImage()
// Display image and begin preloading neighbors.
//
showImage: function(){
Element.hide('loading');
new Effect.Appear('lightboxImage', { duration: resizeDuration, queue: 'end', afterFinish: function(){ myLightbox.updateDetails(); } });
this.preloadNeighborImages();
},
//
// updateDetails()
// Display caption, image number, and bottom nav.
//
updateDetails: function() {
// if caption is not null
if(imageArray[activeImage][1]){
Element.show('caption');
Element.setInnerHTML( 'caption', imageArray[activeImage][1]);
}
// if image is part of set display 'Image x of x'
if(imageArray.length > 1){
Element.show('numberDisplay');
Element.setInnerHTML( 'numberDisplay', "Image " + eval(activeImage + 1) + " of " + imageArray.length);
}
new Effect.Parallel(
[ new Effect.SlideDown( 'imageDataContainer', { sync: true, duration: resizeDuration, from: 0.0, to: 1.0 }),
new Effect.Appear('imageDataContainer', { sync: true, duration: resizeDuration }) ],
{ duration: resizeDuration, afterFinish: function() {
// update overlay size and update nav
var arrayPageSize = getPageSize();
Element.setHeight('overlay', arrayPageSize[1]);
myLightbox.updateNav();
}
}
);
},
//
// updateNav()
// Display appropriate previous and next hover navigation.
//
updateNav: function() {
Element.show('hoverNav');
// if not first image in set, display prev image button
if(activeImage != 0){
Element.show('prevLink');
document.getElementById('prevLink').onclick = function() {
myLightbox.changeImage(activeImage - 1); return false;
}
}
// if not last image in set, display next image button
if(activeImage != (imageArray.length - 1)){
Element.show('nextLink');
document.getElementById('nextLink').onclick = function() {
myLightbox.changeImage(activeImage + 1); return false;
}
}
this.enableKeyboardNav();
},
//
// enableKeyboardNav()
//
enableKeyboardNav: function() {
document.onkeydown = this.keyboardAction;
},
//
// disableKeyboardNav()
//
disableKeyboardNav: function() {
document.onkeydown = '';
},
//
// keyboardAction()
//
keyboardAction: function(e) {
if (e == null) { // ie
keycode = event.keyCode;
escapeKey = 27;
} else { // mozilla
keycode = e.keyCode;
escapeKey = e.DOM_VK_ESCAPE;
}
key = String.fromCharCode(keycode).toLowerCase();
if((key == 'x') || (key == 'o') || (key == 'c') || (keycode == escapeKey)){ // close lightbox
myLightbox.end();
} else if((key == 'p') || (keycode == 37)){ // display previous image
if(activeImage != 0){
myLightbox.disableKeyboardNav();
myLightbox.changeImage(activeImage - 1);
}
} else if((key == 'n') || (keycode == 39)){ // display next image
if(activeImage != (imageArray.length - 1)){
myLightbox.disableKeyboardNav();
myLightbox.changeImage(activeImage + 1);
}
}
},
//
// preloadNeighborImages()
// Preload previous and next images.
//
preloadNeighborImages: function(){
if((imageArray.length - 1) > activeImage){
preloadNextImage = new Image();
preloadNextImage.src = imageArray[activeImage + 1][0];
}
if(activeImage > 0){
preloadPrevImage = new Image();
preloadPrevImage.src = imageArray[activeImage - 1][0];
}
},
//
// end()
//
end: function() {
this.disableKeyboardNav();
Element.hide('lightbox');
new Effect.Fade('overlay', { duration: overlayDuration});
showSelectBoxes();
showFlash();
}
}
// -----------------------------------------------------------------------------------
//
// getPageScroll()
// Returns array with x,y page scroll values.
// Core code from - quirksmode.com
//
function getPageScroll(){
var xScroll, yScroll;
if (self.pageYOffset) {
yScroll = self.pageYOffset;
xScroll = self.pageXOffset;
} else if (document.documentElement && document.documentElement.scrollTop){ // Explorer 6 Strict
yScroll = document.documentElement.scrollTop;
xScroll = document.documentElement.scrollLeft;
} else if (document.body) {// all other Explorers
yScroll = document.body.scrollTop;
xScroll = document.body.scrollLeft;
}
arrayPageScroll = new Array(xScroll,yScroll)
return arrayPageScroll;
}
// -----------------------------------------------------------------------------------
//
// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.com
// Edit for Firefox by pHaez
//
function getPageSize(){
var xScroll, yScroll;
if (window.innerHeight && window.scrollMaxY) {
xScroll = window.innerWidth + window.scrollMaxX;
yScroll = window.innerHeight + window.scrollMaxY;
} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
xScroll = document.body.scrollWidth;
yScroll = document.body.scrollHeight;
} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
xScroll = document.body.offsetWidth;
yScroll = document.body.offsetHeight;
}
var windowWidth, windowHeight;
// console.log(self.innerWidth);
// console.log(document.documentElement.clientWidth);
if (self.innerHeight) { // all except Explorer
if(document.documentElement.clientWidth){
windowWidth = document.documentElement.clientWidth;
} else {
windowWidth = self.innerWidth;
}
windowHeight = self.innerHeight;
} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
windowWidth = document.documentElement.clientWidth;
windowHeight = document.documentElement.clientHeight;
} else if (document.body) { // other Explorers
windowWidth = document.body.clientWidth;
windowHeight = document.body.clientHeight;
}
// for small pages with total height less then height of the viewport
if(yScroll < windowHeight){
pageHeight = windowHeight;
} else {
pageHeight = yScroll;
}
// console.log("xScroll " + xScroll)
// console.log("windowWidth " + windowWidth)
// for small pages with total width less then width of the viewport
if(xScroll < windowWidth){
pageWidth = xScroll;
} else {
pageWidth = windowWidth;
}
// console.log("pageWidth " + pageWidth)
arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight)
return arrayPageSize;
}
// -----------------------------------------------------------------------------------
//
// getKey(key)
// Gets keycode. If 'x' is pressed then it hides the lightbox.
//
function getKey(e){
if (e == null) { // ie
keycode = event.keyCode;
} else { // mozilla
keycode = e.which;
}
key = String.fromCharCode(keycode).toLowerCase();
if(key == 'x'){
}
}
// -----------------------------------------------------------------------------------
//
// listenKey()
//
function listenKey () { document.onkeypress = getKey; }
// ---------------------------------------------------
function showSelectBoxes(){
var selects = document.getElementsByTagName("select");
for (i = 0; i != selects.length; i++) {
selects[i].style.visibility = "visible";
}
}
// ---------------------------------------------------
function hideSelectBoxes(){
var selects = document.getElementsByTagName("select");
for (i = 0; i != selects.length; i++) {
selects[i].style.visibility = "hidden";
}
}
// ---------------------------------------------------
function showFlash(){
var flashObjects = document.getElementsByTagName("object");
for (i = 0; i < flashObjects.length; i++) {
flashObjects[i].style.visibility = "visible";
}
var flashEmbeds = document.getElementsByTagName("embed");
for (i = 0; i < flashEmbeds.length; i++) {
flashEmbeds[i].style.visibility = "visible";
}
}
// ---------------------------------------------------
function hideFlash(){
var flashObjects = document.getElementsByTagName("object");
for (i = 0; i < flashObjects.length; i++) {
flashObjects[i].style.visibility = "hidden";
}
var flashEmbeds = document.getElementsByTagName("embed");
for (i = 0; i < flashEmbeds.length; i++) {
flashEmbeds[i].style.visibility = "hidden";
}
}
// ---------------------------------------------------
//
// pause(numberMillis)
// Pauses code execution for specified time. Uses busy code, not good.
// Help from Ran Bar-On [[email protected]]
//
function pause(ms){
var date = new Date();
curDate = null;
do{var curDate = new Date();}
while( curDate - date < ms);
}
/*
function pause(numberMillis) {
var curently = new Date().getTime() + sender;
while (new Date().getTime();
}
*/
// ---------------------------------------------------
function initLightbox() { myLightbox = new Lightbox(); }
//Event.observe(window, 'load', initLightbox, false);
我继续进行此工作，并有一个临时解决方案，直到Lightbox2大型机在覆盖层上具有有效的alt标签为止（尝试使用当前的11.1版本，但它们无法正常工作）。我在第122行之后添加了setAlt部分
setAlt: function(element,alt) {
element = $(element);
element.alt = alt;
},
，然后在图像预加载器部分中添加alt调用（在第440行附近）。我尝试在此代码中调用ALT的值，但是最好能得到的是“未定义”，因此我设置了一个静态值。
imgPreloader = new Image();
// once image is preloaded, resize image container
imgPreloader.onload=function(){
Element.setSrc('lightboxImage', imageArray[activeImage][0]);
Element.setAlt('lightboxImage', 'Caption below');
// Element.setAlt ('lightboxImage', imageArray[activeImage][0].alt);
//which returned alt="undefined". Couldn't figure out setting VAR
myLightbox.resizeImageContainer(imgPreloader.width, imgPreloader.height);