Home Web Front-end CSS Tutorial Solution to the cascading order problem caused by the opacity attribute of CSS3

Solution to the cascading order problem caused by the opacity attribute of CSS3

Mar 13, 2017 pm 05:58 PM
css3 cascade

This article mainly introduces the method to solve the cascading order problem caused by the opacityproperty of CSS3. It mainly focuses on the problem that layers with an opacity property value less than 1 will cover other layers. It needs to Friends can refer to

In a recent work, when using the opacity attribute to achieve overall transparency of the page, a problem was discovered. If two layers overlap, the layer with the opacity attribute and the attribute value less than 1 will overwrite the subsequent layer. So I did an experiment to verify the level of opacity.

The cascading rule in web pages is like this: If neither layer has definition position attribute is absolute or relative attribute, which layer's HTML code is placed behind , which layer is displayed on top. If the position attribute is specified and the z-index attribute is set, the one with the larger value will be on top.

Found the problem

For ordinary layers that do not have z-index activated, if that layer uses an opacity attribute with an attribute value less than 1, which layer will shown above. Let's make a demo. The code is as follows:

 <!DOCTYPE html>   
 <html>   
 <head>   
 <title>带有 opacity 的层叠问题</title>   
 <style>   
 html{padding:40px;}   
 .dd{width:100px;height:100px;}   
a{background:red;}   

b{background:blue;margin-left:20px;margin-top:-80px;}   

c{background:green;margin-left:40px;margin-top:-80px;}   

</style>   
</head>   
<body>   
<p id=”a”></p>   
<p id=”b”></p>   
<p id=”c”></p>   
</body>   
</html>
Copy after login


After saving it as an html file and opening it, you can see the normal order
Solution to the cascading order problem caused by the opacity attribute of CSS3

At this time, we are# a plus attribute opacity: 0.9 The magic happens, it covers the other two layers
Solution to the cascading order problem caused by the opacity attribute of CSS3

Only when another layer (for example: #c) is also set to a value less than 1 After the opacity value (for example: 0.8), the following #c can install normal rules to cover #a.
Solution to the cascading order problem caused by the opacity attribute of CSS3

In this way, a layer with an opacity attribute less than 1 is added, raising it to a higher level. As for the scientific principles inside, I haven't figured it out, maybe it's a small bug. But sometimes this is something we don't want to happen.

Solution to the problem

So how to solve this problem? As mentioned before, under normal circumstances, the layer with position and z-index specified has a higher level than the ordinary layer. So how does the layer with opacity specified compare with the layer with position specified? Let's add position: relative to #b and see. The style code at this time is as follows:

 #a{background:red;opacity:0.9;}   
b{background:blue;margin-left:20px;margin-top:-80px;position:relative;}   

c{background:green;margin-left:40px;margin-top:-80px;opacity:0.8;}
Copy after login


After saving and refreshing, you will see the effect like this:

Solution to the cascading order problem caused by the opacity attribute of CSS3

In other words, after using the relative position attribute on a layer, the level can be the same as the opacity. After that, the cascading display will be performed according to the normal order (in the subsequent experiments, I also tested the absolute attribute value. The result behaves the same as the relative attribute value). When we cancel the opacity attribute of #c, we can see that #c is ranked at the bottom.
Solution to the cascading order problem caused by the opacity attribute of CSS3

It’s not over yet, I just activated the position: relative attribute for #b before, and I haven’t used z-index yet. We set the z-index of #b (for example: 100). Obviously, #b becomes the top level.
Solution to the cascading order problem caused by the opacity attribute of CSS3


Conclusion:

The layer using the position attribute value of absolute and relative will be higher than the ordinary layer level. The layer using the opacity attribute less than 1 is also higher than the ordinary layer and is the same layer as the layer with the specified position. However, it does not support the z-index attribute, so the layer with the specified position can use the z-index attribute to cover the band. Layers with an opacity property less than 1.

The above is the detailed content of Solution to the cascading order problem caused by the opacity attribute of CSS3. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
1 months ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to achieve wave effect with pure CSS3? (code example) How to achieve wave effect with pure CSS3? (code example) Jun 28, 2022 pm 01:39 PM

How to achieve wave effect with pure CSS3? This article will introduce to you how to use SVG and CSS animation to create wave effects. I hope it will be helpful to you!

Use CSS skillfully to realize various strange-shaped buttons (with code) Use CSS skillfully to realize various strange-shaped buttons (with code) Jul 19, 2022 am 11:28 AM

This article will show you how to use CSS to easily realize various weird-shaped buttons that appear frequently. I hope it will be helpful to you!

How to hide elements in css without taking up space How to hide elements in css without taking up space Jun 01, 2022 pm 07:15 PM

Two methods: 1. Using the display attribute, just add the "display:none;" style to the element. 2. Use the position and top attributes to set the absolute positioning of the element to hide the element. Just add the "position:absolute;top:-9999px;" style to the element.

How to implement lace borders in css3 How to implement lace borders in css3 Sep 16, 2022 pm 07:11 PM

In CSS, you can use the border-image attribute to achieve a lace border. The border-image attribute can use images to create borders, that is, add a background image to the border. You only need to specify the background image as a lace style; the syntax "border-image: url (image path) offsets the image border width inward. Whether outset is repeated;".

It turns out that text carousel and image carousel can also be realized using pure CSS! It turns out that text carousel and image carousel can also be realized using pure CSS! Jun 10, 2022 pm 01:00 PM

How to create text carousel and image carousel? The first thing everyone thinks of is whether to use js. In fact, text carousel and image carousel can also be realized using pure CSS. Let’s take a look at the implementation method. I hope it will be helpful to everyone!

css3 what is adaptive layout css3 what is adaptive layout Jun 02, 2022 pm 12:05 PM

Adaptive layout, also known as "responsive layout", refers to a web page layout that can automatically recognize the screen width and make corresponding adjustments; such a web page can be compatible with multiple different terminals instead of making a specific version for each terminal. . Adaptive layout was born to solve the problem of mobile web browsing, and can provide a good user experience for users using different terminals.

How to enlarge the image by clicking the mouse in css3 How to enlarge the image by clicking the mouse in css3 Apr 25, 2022 pm 04:52 PM

Implementation method: 1. Use the ":active" selector to select the state of the mouse click on the picture; 2. Use the transform attribute and scale() function to achieve the picture magnification effect, the syntax "img:active {transform: scale(x-axis magnification, y Axis magnification);}".

Does css3 animation effect have deformation? Does css3 animation effect have deformation? Apr 28, 2022 pm 02:20 PM

The animation effect in css3 has deformation; you can use "animation: animation attribute @keyframes ..{..{transform: transformation attribute}}" to achieve deformation animation effect. The animation attribute is used to set the animation style, and the transform attribute is used to set the deformation style. .

See all articles