Javascript 如果源设置为透明像素，则图像标记背景图像不显示

在将src属性设置为透明像素后，在img标记上显示背景图像时遇到一些问题

HTML:

JavaScript:

var transparentPng = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAE0lEQVR4XgXAAQ0AAABAMP1L38IF/gL+/AQ1bQAAAABJRU5ErkJggg==";
var spriteUrl = "url(http://upload.wikimedia.org/wikipedia/commons/9/9a/Google_Chrome_screenshot.png)"

// Why doesn't background image show?
$(".test-class").attr("src", transparentPng);

// It does show if src is set to a broken URL, though.
//$(".test-class").attr("src", "invalidurl");

$(".test-class").css("background-image", spriteUrl);

下面是一个实时测试用例：

我真正想做的是显示一个精灵，但是由于精灵图像非常大，并且只在事件上显示，所以我使用image标记的src属性来显示初始图像。当事件发生时，我想用精灵替换该图像。为了实现这一点，我的想法是将源图像替换为透明像素，并设置背景图像。但由于某些原因，背景图像没有显示出来

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您能告诉我需要在测试用例中更改什么以使较大的图像（表示精灵）可见吗？

您使用的图像似乎有问题

使用此图像。它起作用了

var transparentPng = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=";

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base64映像不知何故已损坏，请参阅

var transparentPng = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAE0lEQVR4XgXAAQ0AAABAMP1L38IF/gL+/AQ1bQAAAABJRU5ErkJggg==";
var spriteUrl = "url(http://upload.wikimedia.org/wikipedia/commons/9/9a/Google_Chrome_screenshot.png)"

// Why doesn't background image show?
$(".test-class").attr("src", transparentPng);

// It does show if src is set to a broken URL, though.
//$(".test-class").attr("src", "invalidurl");

$(".test-class").css("background-image", spriteUrl);

var transparentPng = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=";

var transparentPng = "data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7";