兼容IE、Firefox的背景半透明内容不透明设置_html/css_WEB-ITnose
首先要说明的是背景是内容的祖先元素。如果是兄弟节点那就没有必要记录这篇文章了。
记录一下，知其然也知其所以然。
IE8-特点：
1.不支持"opcity:0.5;"这种写法，只支持"filter:alpha(opacity=50)"。
2.如果背景元素拥有css属性设置了z-index的值（除默认值auto外),则内容会随着背景元素一起半透明
3.如果背景元素的内容元素本身或其祖先节点（这些祖先节点是背景元素的后代节点）没有设置css定位属性position:relative/absolute/fixed。则内容也会随着背景元素一起半透明。
4.支持"background：rgb(0,0,0)"设置背景颜色，但是不支持“background：rgba(0,0,0,0.5)”这种设置背景颜色的同事设置半透明的方式。
IE9+、chrome、Firefox特点：
1.支持"opacity:0.5",但是内容会随背景一起半透明
1.支持“background：rgba(0,0,0,0.5)”这种设置背景颜色的同事设置背景半透明但内容不透明的方式。
2.如果同事使用opacity=0.5和rgba不透明度为0.5，那么效果是在元素为opacity所设置的不透明度的情况下背景再次按rgba的方式半透明。最终背景的半透明度为opacity*rgba=0.5*0.5=0.25。
IE9+还有一个特点就是同时支持opcity:0.5和"filter:alpha(opacity=50)"这种方式。所以rgba和filter一起用会出现第三项的情况。
所以综合上述的浏览器特点，兼容所有浏览器的方案是背景元素设置样式为
/*不能设置z-index,根据情况设置需要的background的颜色,chrome/firefox中第一句起作用；IE中后两句起作用*/ .background{ background: rgba(0,0,0,0.5);/*firefox、chrome*/ background: #000\9;/*IE*/ filter: alpha(opacity=50);/*IE*/ }代码解读为在Firefox、chrome下后两句不会被识别，所以使用rgba做背景半透明内容不透明；IE下第二句的background会覆盖第一句话，所以最终结果是后两句起到作用。
内容元素的样式为
/*可以设置元素或其祖先节点为定位样式relative/absolute/fixed*/.content{ position:relative; }完整实例
<!DOCTYPE html><html lang="ch-cn"> <head> <meta charset="utf-8"> <style type="text/css"> html,body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, code, form, fieldset, legend, input, button, textarea, p, blockquote, th, td{ margin: 0; padding:0; } *{ -webkit-box-sizing: border-box; -moz-box-sizing: border-box; box-sizing: border-box; } /*不能设置z-index,根据情况设置需要的background的颜色,chrome/firefox中第一句起作用；IE中后两句起作用*/ .background{ background: rgba(0,0,0,0.5);/*firefox、chrome*/ background: #000\9;/*IE*/ filter: alpha(opacity=50);/*IE*/ } /*可以设置元素或其祖先节点为定位样式relative/absolute/fixed*/ .content{ position:relative; } </style> </head> <body> <div style="width:50px;height:50px;border:1px solid;background: red;"></div> <div class="background" style="width: 200px;height: 200px;"> <div class="content" style="width: 50px;height:50px;background: red;"></div> </div></html>效果图如下
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1377
52
What is the purpose of the <progress> element?
Mar 21, 2025 pm 12:34 PM
The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati
What is the purpose of the <datalist> element?
Mar 21, 2025 pm 12:33 PM
The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159
What is the purpose of the <meter> element?
Mar 21, 2025 pm 12:35 PM
The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex
What are the best practices for cross-browser compatibility in HTML5?
Mar 17, 2025 pm 12:20 PM
Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.
How do I use HTML5 form validation attributes to validate user input?
Mar 17, 2025 pm 12:27 PM
The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.
What is the viewport meta tag? Why is it important for responsive design?
Mar 20, 2025 pm 05:56 PM
The article discusses the viewport meta tag, essential for responsive web design on mobile devices. It explains how proper use ensures optimal content scaling and user interaction, while misuse can lead to design and accessibility issues.
What is the purpose of the <iframe> tag? What are the security considerations when using it?
Mar 20, 2025 pm 06:05 PM
The article discusses the <iframe> tag's purpose in embedding external content into webpages, its common uses, security risks, and alternatives like object tags and APIs.
Gitee Pages static website deployment failed: How to troubleshoot and resolve single file 404 errors?
Apr 04, 2025 pm 11:54 PM
GiteePages static website deployment failed: 404 error troubleshooting and resolution when using Gitee...
