下面是一个简单的解决方案，适用于现代浏览器，使用纯CSS和一个'before'伪元素，就像Matthew Wilcoxson的解决方案一样。

为了避免在JavaScript中需要访问伪元素来更改图像和其他属性，只需使用inherit作为值，并通过父元素(这里是body)访问它们。

body::before {
    content: ""; /* Important */
    z-index: -1; /* Important */
    position: inherit;
    left: inherit;
    top: inherit;
    width: inherit;
    height: inherit;
    background-image: inherit;
    background-size: cover;
    filter: blur(8px);
}

body {
  background-image: url("xyz.jpg");
  background-size: 0 0;  /* Image should not be drawn here */
  width: 100%;
  height: 100%;
  position: fixed; /* Or absolute for scrollable backgrounds */
}

pen

取消了对额外元素的需求，同时使内容适合文档流，而不是像其他解决方案那样固定/绝对。

通过使用

.content { /* this is needed or the background will be offset by a few pixels at the top */ overflow: auto; position: relative; } .content::before { content: ""; position: fixed; left: 0; right: 0; z-index: -1; display: block; background-image: url('https://i.imgur.com/lL6tQfy.png'); background-size:cover; width: 100%; height: 100%; -webkit-filter: blur(5px); -moz-filter: blur(5px); -o-filter: blur(5px); -ms-filter: blur(5px); filter: blur(5px); } <div class="content"> Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. </div>

编辑如果你想删除边缘的白色边框，使用宽度和高度为110%，左侧和顶部为-5%。这将放大你的背景-但不应该有纯色从边缘流出。感谢Chad Fawcett的建议。

.content { /* this is needed or the background will be offset by a few pixels at the top */ overflow: auto; position: relative; } .content::before { content: ""; position: fixed; top: -5%; left: -5%; right: -5%; z-index: -1; display: block; background-image: url('https://i.imgur.com/lL6tQfy.png'); background-size:cover; width: 110%; height: 110%; -webkit-filter: blur(5px); -moz-filter: blur(5px); -o-filter: blur(5px); -ms-filter: blur(5px); filter: blur(5px); } <div class="content"> Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. </div>

看看这支笔。

您必须使用两个不同的容器，一个用于背景图像，另一个用于内容。

在本例中，我创建了两个容器，.background-image和.content。

它们都被放置在位置:固定和左:0;右:0;。显示它们的差异来自为元素设置的不同的z-index值。

.background-image { position: fixed; left: 0; right: 0; z-index: 1; display: block; background-image: url('https://i.imgur.com/lL6tQfy.png'); width: 1200px; height: 800px; -webkit-filter: blur(5px); -moz-filter: blur(5px); -o-filter: blur(5px); -ms-filter: blur(5px); filter: blur(5px); } .content { position: fixed; left: 0; right: 0; z-index: 9999; margin-left: 20px; margin-right: 20px; } <div class="background-image"></div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis aliquam erat in ante malesuada, facilisis semper nulla semper. Phasellus sapien neque, faucibus in malesuada quis, lacinia et libero. Sed sed turpis tellus. Etiam ac aliquam tortor, eleifend rhoncus metus. Ut turpis massa, sollicitudin sit amet molestie a, posuere sit amet nisl. Mauris tincidunt cursus posuere. Nam commodo libero quis lacus sodales, nec feugiat ante posuere. Donec pulvinar auctor commodo. Donec egestas diam ut mi adipiscing, quis lacinia mauris condimentum. Quisque quis odio venenatis, venenatis nisi a, vehicula ipsum. Etiam at nisl eu felis vulputate porta.</p> <p>Fusce ut placerat eros. Aliquam consequat in augue sed convallis. Donec orci urna, tincidunt vel dui at, elementum semper dolor. Donec tincidunt risus sed magna dictum, quis luctus metus volutpat. Donec accumsan et nunc vulputate accumsan. Vestibulum tempor, erat in mattis fringilla, elit urna ornare nunc, vel pretium elit sem quis orci. Vivamus condimentum dictum tempor. Nam at est ante. Sed lobortis et lorem in sagittis. In suscipit in est et vehicula.</p> </div>

为Lorem Ipsum的文本道歉。

更新

感谢Matthew Wilcoxson在https://codepen.io/akademy/pen/FlkzB之前使用.content::提供了更好的实现

当然，这不是css解决方案，但你可以使用CDN质子过滤器:

body {
    background: url('https://i0.wp.com/IMAGEURL?w=600&filter=blurgaussian&smooth=1');
}

它来自https://developer.wordpress.com/docs/photon/api/#filter

成功应用背景图像的步骤

确保使用link标签正确链接了HTML和CSS <link rel="stylesheet" ref="yourcssdocument.css"> 我不知道相对目录和子目录，所以我不能评论它 对我来说，最好的方法是在css中使用URL链接

#yourcssdoc .image {
   background-image: url("paste your link here with the quotations")
}

div { background: inherit; width: 250px; height: 350px; position: absolute; overflow: hidden; /* Adding overflow hidden */ } div:before { content: ‘’; width: 300px; height: 400px; background: inherit; position: absolute; left: -25px; /* Giving minus -25px left position */ right: 0; top: -25px; /* Giving minus -25px top position */ bottom: 0; box-shadow: inset 0 0 0 200px rgba(255, 255, 255, 0.3); filter: blur(10px); }