之前公司项目PHP渲染的，莫名其妙标题栏一直转圈，最终发现是备用图片加载失败导致死循环，总结一下问题与解决方案。
通常，图片加载失败会有一个默认的图片，但是如果默认图片也加载失败，就会导致死循环。
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| <img src="http://www.abc.com/1.jpg" onerror="this.src='http://www.abc.com/2.jpg'">
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上述代码，如果2.jpg加载失败，则会走图片的onerror回调，再次加载2.jpg，如果2.jpg还是加载失败，就会再次走onerror回调，再次加载2.jpg，如此循环，浏览器就会卡死转圈。
解决方案：
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| <img src="test.png" alt="Alt Info" onerror="this.classList.add('error');">
|
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| img.error {
position: relative;
display: inline-block;
}
img.error::before {
background: #f5f5f5 url("data:image/svg+xml,%3Csvg class='icon' viewBox='0 0 1024 1024' xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cpath d='M304.128 456.192c48.64 0 88.064-39.424 88.064-88.064s-39.424-88.064-88.064-88.064-88.064 39.424-88.064 88.064 39.424 88.064 88.064 88.064zm0-116.224c15.36 0 28.16 12.288 28.16 28.16s-12.288 28.16-28.16 28.16-28.16-12.288-28.16-28.16 12.288-28.16 28.16-28.16z' fill='%23e6e6e6'/%3E%3Cpath d='M887.296 159.744H136.704C96.768 159.744 64 192 64 232.448v559.104c0 39.936 32.256 72.704 72.704 72.704h198.144L500.224 688.64l-36.352-222.72 162.304-130.56-61.44 143.872 92.672 214.016-105.472 171.008h335.36C927.232 864.256 960 832 960 791.552V232.448c0-39.936-32.256-72.704-72.704-72.704zm-138.752 71.68v.512H857.6c16.384 0 30.208 13.312 30.208 30.208v399.872L673.28 408.064l75.264-176.64zM304.64 792.064H165.888c-16.384 0-30.208-13.312-30.208-30.208v-9.728l138.752-164.352 104.96 124.416-74.752 79.872zm81.92-355.84l37.376 228.864-.512.512-142.848-169.984c-3.072-3.584-9.216-3.584-12.288 0L135.68 652.8V262.144c0-16.384 13.312-30.208 30.208-30.208h474.624L386.56 436.224zm501.248 325.632c0 16.896-13.312 30.208-29.696 30.208H680.96l57.344-93.184-87.552-202.24 7.168-7.68 229.888 272.896z' fill='%23e6e6e6'/%3E%3C/svg%3E") no-repeat center / 50% 50%;
}
img.error::after {
content: attr(alt);
}
|
来源：
现代图片性能优化及体验优化指南 - 图片资源的容错及可访问性处理 - ChokCoco - 博客园 (cnblogs.com)
图片加载失败后CSS样式处理最佳实践 « 张鑫旭-鑫空间-鑫生活 (zhangxinxu.com)
