为什么这个幻灯片不会起作用

好的，我要做的是使用下面的示例创建幻灯片放映。 问题是动画不起作用。 设计明智它看起来不错，但图像不会在我的浏览器中旋转。 是因为我必须使用window.setTimeout（）谢谢！

http://tutorialzine.com/2010/09/html5-canvas-slideshow-jquery/

也有人似乎有类似的问题，但不像我的代码相同：

为什么这个幻灯片代码不起作用？

inheritance人HTML：

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然后我们有CSS：

 #slideshow{ background-color:#F5F5F5; border:1px solid #FFFFFF; height:340px; margin:150px auto 0; position:relative; width:640px; -moz-box-shadow:0 0 22px #111; -webkit-box-shadow:0 0 22px #111; box-shadow:0 0 22px #111; } #slideshow ul{ height:320px; left:10px; list-style:none outside none; overflow:hidden; position:absolute; top:10px; width:620px; } #slideshow li{ position:absolute; display:none; z-index:10; } #slideshow li:first-child{ display:block; z-index:1000; } #slideshow .slideActive{ z-index:1000; } #slideshow canvas{ display:none; position:absolute; z-index:100; } #slideshow .arrow{ height:86px; width:60px; position:absolute; background:url('img/arrows.png') no-repeat; top:50%; margin-top:-43px; cursor:pointer; z-index:5000; } #slideshow .previous{ background-position:left top;left:0;} #slideshow .previous:hover{ background-position:left bottom;} #slideshow .next{ background-position:right top;right:0;} #slideshow .next:hover{ background-position:right bottom;} 

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现在javascript：

 $(window).load(function(){ // We are listening to the window.load event, so we can be sure // that the images in the slideshow are loaded properly. // Testing wether the current browser supports the canvas element: var supportCanvas = 'getContext' in document.createElement('canvas'); // The canvas manipulations of the images are CPU intensive, // this is why we are using setTimeout to make them asynchronous // and improve the responsiveness of the page. var slides = $('#slideshow li'), current = 0, slideshow = {width:0,height:0}; setTimeout(function(){ if(supportCanvas){ $('#slideshow img').each(function(){ if(!slideshow.width){ // Saving the dimensions of the first image: slideshow.width = this.width; slideshow.height = this.height; } // Rendering the modified versions of the images: createCanvasOverlay(this); }); } $('#slideshow .arrow').click(function(){ var li = slides.eq(current), canvas = li.find('canvas'), nextIndex = 0; // Depending on whether this is the next or previous // arrow, calculate the index of the next slide accordingly. if($(this).hasClass('next')){ nextIndex = current >= slides.length-1 ? 0 : current+1; } else { nextIndex = current <= 0 ? slides.length-1 : current-1; } var next = slides.eq(nextIndex); if(supportCanvas){ // This browser supports canvas, fade it into view: canvas.fadeIn(function(){ // Show the next slide below the current one: next.show(); current = nextIndex; // Fade the current slide out of view: li.fadeOut(function(){ li.removeClass('slideActive'); canvas.hide(); next.addClass('slideActive'); }); }); } else { // This browser does not support canvas. // Use the plain version of the slideshow. current=nextIndex; next.addClass('slideActive').show(); li.removeClass('slideActive').hide(); } }); },100); // This function takes an image and renders // a version of it similar to the Overlay blending // mode in Photoshop. function createCanvasOverlay(image){ var canvas = document.createElement('canvas'), canvasContext = canvas.getContext("2d"); // Make it the same size as the image canvas.width = slideshow.width; canvas.height = slideshow.height; // Drawing the default version of the image on the canvas: canvasContext.drawImage(image,0,0); // Taking the image data and storing it in the imageData array: var imageData = canvasContext.getImageData(0,0,canvas.width,canvas.height), data = imageData.data; // Loop through all the pixels in the imageData array, and modify // the red, green, and blue color values. for(var i = 0,z=data.length;i<z;i++){ // The values for red, green and blue are consecutive elements // in the imageData array. We modify the three of them at once: data[i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255)); data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255)); data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255)); // After the RGB channels comes the alpha value, which we leave the same. ++i; } // Putting the modified imageData back on the canvas. canvasContext.putImageData(imageData,0,0,0,0,imageData.width,imageData.height); // Inserting the canvas in the DOM, before the image: image.parentNode.insertBefore(canvas,image); } }); 

Answer 1

仅供参考，谷歌目前处于下行状态： http ： //www.websitedown.info/ajax.googleapis.com ，因此可能无法加载jquery。