我正在使用来自Google基于HTML5的网络应用
简而言之，本书的工作原理是将内容直接放在DOM（搜索引擎友好）中并使用javascript操作它。页面翻转动画被绘制到重叠的画布元素上。
当我开始在我的书中添加链接和联系表单时，我遇到了问题。由于某种原因，链接和输入元素不是“可点击的”。
我已经创建了一个jsFiddle here 来演示。
我认为这可能是一个z索引问题：重叠的画布z-index设置为100. Page z-indices从0开始，一直向前到书的前面。如果我使用更高的z-index将链接/输入带到前面怎么办？
但改变违规元素的z指数并没有解决问题。无论如何，页面本身是使用z-indices分层的，所以即使将链接/输入带到顶层也可以工作，它也不是一个可行的解决方案，因为这样的链接就不会与各自的页面正确分层。
如何解决此问题： 在画布下/通过画布使链接和输入元素“可点击”？
HTML：
<body>
<div id="book">
<canvas id="pageflip-canvas"></canvas>
<div id="pages">
<section>
<div>
<h2>Test Page</h2>
<p>This demo is fantastic! ...apart from the fact that link and input elements aren't supported. The canvas element and JS on which the entire magic relies, renders both "unclickable" - a major drawback. See below:</p>
<a href="#">Click me!</a>
<input type="text"></input>
</div>
</section>
<section>
<div>
<h2>History</h2>
<p>Canvas was initially introduced by Apple for use inside their own Mac OS X WebKit component, powering applications like Dashboard widgets and the Safari browser. Later, it was adopted by Gecko browsers and Opera and standardized by the WHATWG on new proposed specifications for next generation web technologies.</p>
</div>
</section>
</div>
</div>
</body>
CSS：
body, h2, p {
margin: 0;
padding: 0;
}
body {
background-color: #444;
color: #333;
font-family: Helvetica, sans-serif;
}
#book {
background: url("https://dl.dropboxusercontent.com/u/3799114/page-flip-demo/book.png") no-repeat;
position: absolute;
width: 830px;
height: 260px;
left: 50%;
top: 50%;
margin-left: -400px;
margin-top: -125px;
}
#pages section {
background: url("https://dl.dropboxusercontent.com/u/3799114/page-flip-demo/paper.png") no-repeat;
display: block;
width: 400px;
height: 250px;
position: absolute;
left: 415px;
top: 5px;
overflow: hidden;
}
#pages section>div {
display: block;
width: 400px;
height: 250px;
font-size: 12px;
}
#pages section p,
#pages section h2 {
padding: 3px 35px;
line-height: 1.4em;
text-align: justify;
}
#pages section h2{
margin: 15px 0 10px;
}
#pageflip-canvas {
position: absolute;
z-index: 100;
}
jQuery的：
(function() {
// Dimensions of the whole book
var BOOK_WIDTH = 830;
var BOOK_HEIGHT = 260;
// Dimensions of one page in the book
var PAGE_WIDTH = 400;
var PAGE_HEIGHT = 250;
// Vertical spacing between the top edge of the book and the papers
var PAGE_Y = ( BOOK_HEIGHT - PAGE_HEIGHT ) / 2;
// The canvas size equals to the book dimensions + this padding
var CANVAS_PADDING = 60;
var page = 0;
var canvas = document.getElementById( "pageflip-canvas" );
var context = canvas.getContext( "2d" );
var mouse = { x: 0, y: 0 };
var flips = [];
var book = document.getElementById( "book" );
// List of all the page elements in the DOM
var pages = book.getElementsByTagName( "section" );
// Organize the depth of our pages and create the flip definitions
for( var i = 0, len = pages.length; i < len; i++ ) {
pages[i].style.zIndex = len - i;
flips.push( {
// Current progress of the flip (left -1 to right +1)
progress: 1,
// The target value towards which progress is always moving
target: 1,
// The page DOM element related to this flip
page: pages[i],
// True while the page is being dragged
dragging: false
} );
}
// Resize the canvas to match the book size
canvas.width = BOOK_WIDTH + ( CANVAS_PADDING * 2 );
canvas.height = BOOK_HEIGHT + ( CANVAS_PADDING * 2 );
// Offset the canvas so that it's padding is evenly spread around the book
canvas.style.top = -CANVAS_PADDING + "px";
canvas.style.left = -CANVAS_PADDING + "px";
// Render the page flip 60 times a second
setInterval( render, 1000 / 60 );
document.addEventListener( "mousemove", mouseMoveHandler, false );
document.addEventListener( "mousedown", mouseDownHandler, false );
document.addEventListener( "mouseup", mouseUpHandler, false );
function mouseMoveHandler( event ) {
// Offset mouse position so that the top of the book spine is 0,0
mouse.x = event.clientX - book.offsetLeft - ( BOOK_WIDTH / 2 );
mouse.y = event.clientY - book.offsetTop;
}
function mouseDownHandler( event ) {
// Make sure the mouse pointer is inside of the book
if (Math.abs(mouse.x) < PAGE_WIDTH) {
if (mouse.x < 0 && page - 1 >= 0) {
// We are on the left side, drag the previous page
flips[page - 1].dragging = true;
}
else if (mouse.x > 0 && page + 1 < flips.length) {
// We are on the right side, drag the current page
flips[page].dragging = true;
}
}
// Prevents the text selection
event.preventDefault();
}
function mouseUpHandler( event ) {
for( var i = 0; i < flips.length; i++ ) {
// If this flip was being dragged, animate to its destination
if( flips[i].dragging ) {
// Figure out which page we should navigate to
if( mouse.x < 0 ) {
flips[i].target = -1;
page = Math.min( page + 1, flips.length );
}
else {
flips[i].target = 1;
page = Math.max( page - 1, 0 );
}
}
flips[i].dragging = false;
}
}
function render() {
// Reset all pixels in the canvas
context.clearRect( 0, 0, canvas.width, canvas.height );
for( var i = 0, len = flips.length; i < len; i++ ) {
var flip = flips[i];
if( flip.dragging ) {
flip.target = Math.max( Math.min( mouse.x / PAGE_WIDTH, 1 ), -1 );
}
// Ease progress towards the target value
flip.progress += ( flip.target - flip.progress ) * 0.2;
// If the flip is being dragged or is somewhere in the middle of the book, render it
if( flip.dragging || Math.abs( flip.progress ) < 0.997 ) {
drawFlip( flip );
}
}
}
function drawFlip( flip ) {
// Strength of the fold is strongest in the middle of the book
var strength = 1 - Math.abs( flip.progress );
// Width of the folded paper
var foldWidth = ( PAGE_WIDTH * 0.5 ) * ( 1 - flip.progress );
// X position of the folded paper
var foldX = PAGE_WIDTH * flip.progress + foldWidth;
// How far the page should outdent vertically due to perspective
var verticalOutdent = 20 * strength;
// The maximum width of the left and right side shadows
var paperShadowWidth = ( PAGE_WIDTH * 0.5 ) * Math.max( Math.min( 1 - flip.progress, 0.5 ), 0 );
var rightShadowWidth = ( PAGE_WIDTH * 0.5 ) * Math.max( Math.min( strength, 0.5 ), 0 );
var leftShadowWidth = ( PAGE_WIDTH * 0.5 ) * Math.max( Math.min( strength, 0.5 ), 0 );
// Change page element width to match the x position of the fold
flip.page.style.width = Math.max(foldX, 0) + "px";
context.save();
context.translate( CANVAS_PADDING + ( BOOK_WIDTH / 2 ), PAGE_Y + CANVAS_PADDING );
// Draw a sharp shadow on the left side of the page
context.strokeStyle = 'rgba(0,0,0,'+(0.05 * strength)+')';
context.lineWidth = 30 * strength;
context.beginPath();
context.moveTo(foldX - foldWidth, -verticalOutdent * 0.5);
context.lineTo(foldX - foldWidth, PAGE_HEIGHT + (verticalOutdent * 0.5));
context.stroke();
// Right side drop shadow
var rightShadowGradient = context.createLinearGradient(foldX, 0, foldX + rightShadowWidth, 0);
rightShadowGradient.addColorStop(0, 'rgba(0,0,0,'+(strength*0.2)+')');
rightShadowGradient.addColorStop(0.8, 'rgba(0,0,0,0.0)');
context.fillStyle = rightShadowGradient;
context.beginPath();
context.moveTo(foldX, 0);
context.lineTo(foldX + rightShadowWidth, 0);
context.lineTo(foldX + rightShadowWidth, PAGE_HEIGHT);
context.lineTo(foldX, PAGE_HEIGHT);
context.fill();
// Left side drop shadow
var leftShadowGradient = context.createLinearGradient(foldX - foldWidth - leftShadowWidth, 0, foldX - foldWidth, 0);
leftShadowGradient.addColorStop(0, 'rgba(0,0,0,0.0)');
leftShadowGradient.addColorStop(1, 'rgba(0,0,0,'+(strength*0.15)+')');
context.fillStyle = leftShadowGradient;
context.beginPath();
context.moveTo(foldX - foldWidth - leftShadowWidth, 0);
context.lineTo(foldX - foldWidth, 0);
context.lineTo(foldX - foldWidth, PAGE_HEIGHT);
context.lineTo(foldX - foldWidth - leftShadowWidth, PAGE_HEIGHT);
context.fill();
// Gradient applied to the folded paper (highlights & shadows)
var foldGradient = context.createLinearGradient(foldX - paperShadowWidth, 0, foldX, 0);
foldGradient.addColorStop(0.35, '#fafafa');
foldGradient.addColorStop(0.73, '#eeeeee');
foldGradient.addColorStop(0.9, '#fafafa');
foldGradient.addColorStop(1.0, '#e2e2e2');
context.fillStyle = foldGradient;
context.strokeStyle = 'rgba(0,0,0,0.06)';
context.lineWidth = 0.5;
// Draw the folded piece of paper
context.beginPath();
context.moveTo(foldX, 0);
context.lineTo(foldX, PAGE_HEIGHT);
context.quadraticCurveTo(foldX, PAGE_HEIGHT + (verticalOutdent * 2), foldX - foldWidth, PAGE_HEIGHT + verticalOutdent);
context.lineTo(foldX - foldWidth, -verticalOutdent);
context.quadraticCurveTo(foldX, -verticalOutdent * 2, foldX, 0);
context.fill();
context.stroke();
context.restore();
}
}）（）;
答案 0 :(得分：1)
我最终发现了一个双重解决方案，需要更改CSS和jQuery（以及第三个要求“修复”一些结果更改）。
第1步：点击链接
为了使链接能够点击，必须将CSS属性 pointer-events （值为 none ）应用于canvas元素。
<强> CSS：
canvas {
pointer-events: none;
}
演示 here 显示现在可点击的链接。
请注意，与IE的兼容性需要以下条件CSS语句：
<!--[if IE]>
<style type="text/css">
canvas {
background: none !important;
}
</style>
<![endif]-->
第2步：点击文字输入
但正如您所看到的，这并未解决文本输入元素的问题，该元素仍然无法单击。 （有趣的是，单选按钮在实施步骤1后工作 - 未包含在演示中）。
这个解决方案在于jQuery（原始演示文件的第82行）：方法 event.preventDefault（）;
此方法用于防止在页面上拖动鼠标时选择默认文本。鼠标拖动动作用于翻页，文本选择使动画的吸引力降低。
删除或注释掉此方法会重新启用文本输入。
<强> jQuery的：
// event.preventDefault(); // comment out this beast
演示 here ，显示现在可点击的文字输入元素。
第3步：使用CSS禁用文字选择
所以现在解决了两个问题 - 无法点击的链接和不可点击的输入元素 - 但是这样做的结果是现在重新启用默认文本选择，使页面翻转动画更少有吸引力的。
解决方案：通过将 -webkit-touch-callout 和用户选择（两者都带有值 none ）应用于内容来禁用文本选择每个“页面”的div。
<强> CSS：
#page-content-div {
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: moz-none;
-ms-user-select: none;
user-select: none;
}
演示 here 显示已完成的图书，其中包含可点击链接和文字输入，并且在页面翻转时没有文字选择。