jsp中给div加背景_web前端入门到实战：详解css3如何给背景图片加颜色遮罩

特定总结一下给背景图层加颜色遮罩的方法。

方法一：通过定位叠加(注意层级)

<div class="wrap1"><div class="inner"> </div></div>.wrap1 {position: relative;width: 1200px;height: 400px;background: rgba(0, 0, 0, .5);}.wrap1 .inner {position: absolute;left: 0;right: 0;top: 0;bottom: 0;background: url(ban8.jpg) no-repeat center center;background-size: cover;z-index: -1;}

方法二：通过伪类元素叠加

<div class="wrap2"></div>.wrap2 {position: relative;width: 1200px;height: 400px;background: url(ban8.jpg) no-repeat center center;background-size: cover;}.wrap2::before {content: "";position: absolute;left: 0;right: 0;bottom: 0;top: 0;background-color: rgba(0, 0, 0, .5);z-index: 2;}

方法三：CSS3颜色叠加background-blend-mode:multiply;(正片叠底)

<div class="wrap3"></div>.wrap3 {position: relative;width: 1200px;height: 400px;background: url(ban8.jpg) rgba(0, 0, 0, .5) no-repeat center center;background-blend-mode: multiply;}

拓展：背景模糊加颜色叠加

.wrap4 {position: relative;width: 1200px;height: 400px;background: url(ban8.jpg) rgba(0, 0, 0, .5) no-repeat center center;background-blend-mode: multiply;filter: blur(2px);overflow: hidden;}

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